feat(spaces): unify collection scope across resource pages

- Treat All as an unfiltered Space collection while preserving exact Space filters. - Keep global resources outside remembered Space context and preserve memo navigation origins. - Surface Space placement consistently across memo, attachment, and visibility UI.
2026-08-26 09:16:28 +08:00 · 2026-08-26 09:16:28 +08:00 · cdd13ca24e
commit cdd13ca24e
parent 05f882e43a
65 changed files with 1818 additions and 249 deletions
--- a/CONTEXT.md
+++ b/CONTEXT.md
@ -31,3 +31,7 @@ _Avoid_: Pending membership, direct add
 **Space membership**:
 An accepted relationship between an active Memos user and a Space, carrying either the `ADMIN` or `USER` Space role.
 _Avoid_: Invitation, application role
+
+**Memo collection scope**:
+The Space-placement dimension applied to memo and derived-resource collections. It is either `all`, which adds no Space predicate, or one exact Space. An unassigned Memo remains part of `all`; unassigned is a placement, not a collection scope.
+_Avoid_: Unassigned scope, no-Space collection
--- a/web/src/components/AppSidebar/AppSidebar.tsx
+++ b/web/src/components/AppSidebar/AppSidebar.tsx
@ -65,7 +65,7 @@ import type { MemoView } from "@/types/proto/api/v1/memo_view_service_pb";
 import { User_Role, UserNotification_Status } from "@/types/proto/api/v1/user_service_pb";
 import { useTranslate } from "@/utils/i18n";
 import MemosLogo from "../MemosLogo";
-import { getSidebarRouteKind } from "./routes";
+import { getSidebarRouteKind, routeSupportsCollectionScope } from "./routes";
 import SidebarRow, { SIDEBAR_ROW_CLASSES, SIDEBAR_ROW_FOCUS_CLASSES, SIDEBAR_ROW_ICON_CLASSES, sidebarRowStateClasses } from "./SidebarRow";
 import SidebarSection, {
  SIDEBAR_SECTION_ACTION_BUTTON_CLASSES,
@ -263,7 +263,6 @@ const CollectionSidebarContent = ({ context }: { context: MemoStatsContext }) =>
    context,
    userName: statsUserName,
    filter: statsFilter,
-    includeSpaceVisibility: !!selectedSpaceName,
    enabled: authInitialized && instanceInitialized && (md || mobileOpen),
  });

@ -273,7 +272,8 @@ const CollectionSidebarContent = ({ context }: { context: MemoStatsContext }) =>
  // clicks must land somewhere that renders the filtered feed.
  const onCollectionRoute = isMemoScopeRoute(location.pathname) || !!profileMatch;
  const filterTarget = onCollectionRoute ? undefined : context === "explore" ? ROUTES.EXPLORE : ROUTES.HOME;
-  const tagStateScope = `${statsUserName ?? context}${selectedSpaceName ? `:${selectedSpaceName}` : ""}`;
+  const tagStateScope =
+    context === "profile" ? (statsUserName ?? context) : `${statsUserName ?? context}${selectedSpaceName ? `:${selectedSpaceName}` : ""}`;

  return (
    <div className={SIDEBAR_SECTION_STACK_CLASSES}>
@ -405,6 +405,8 @@ const MemoDetailSidebarContent = () => {
  return (
    <MemoDetailSidebar
      memo={memoDetail.memo}
+      parentPage={memoDetail.from}
+      parentScope={memoDetail.fromScope}
      forceReadonly={memoDetail.readonly}
      onShareImageOpen={memoDetail.onShareImageOpen}
      className="pb-2"
@ -414,8 +416,6 @@ const MemoDetailSidebarContent = () => {

 const RouteSidebarContent = () => {
  const location = useLocation();
-  const currentUser = useCurrentUser();
-  const { memoDetail } = useAppSidebar();
  const kind = getSidebarRouteKind(location.pathname);
  if (kind === "home" || kind === "archived" || kind === "explore" || kind === "profile") {
    return <CollectionSidebarContent context={kind} />;
@ -424,10 +424,8 @@ const RouteSidebarContent = () => {
  if (kind === "attachments") return <AttachmentsSidebarContent />;
  if (kind === "inbox") return <InboxSidebarContent />;
  if (kind === "settings") return <SettingsSidebarContent />;
-  if (kind === "memo" && memoDetail) return <MemoDetailSidebarContent />;
-  // Routes without a specific tenant (about, error pages, unknown paths, memo detail
-  // before the page publishes its descriptor) fall back to the default library content.
-  return <CollectionSidebarContent context={currentUser ? "home" : "explore"} />;
+  if (kind === "memo") return <MemoDetailSidebarContent />;
+  return null;
 };

 interface GlobalNavItem {
@ -477,10 +475,8 @@ const GlobalNavigation = () => {
  const location = useLocation();
  const navigate = useNavigate();
  const currentUser = useCurrentUser();
-  const { data: notifications = [] } = useNotifications();
  const { memoDetail, memoScope, setMemoScope, setMobileOpen } = useAppSidebar();
  const { filters } = useMemoFilterContext();
-  const unreadCount = notifications.filter((notification) => notification.status === UserNotification_Status.UNREAD).length;
  const routeKind = getSidebarRouteKind(location.pathname);
  const resolvedScope = resolveMemoScope(location.pathname, {
    currentUsername: currentUser?.username,
@ -519,15 +515,7 @@ const GlobalNavigation = () => {
          label: t("common.attachments"),
          path: ROUTES.ATTACHMENTS,
          icon: PaperclipIcon,
-          active: location.pathname === ROUTES.ATTACHMENTS,
-        },
-        {
-          id: "inbox",
-          label: t("common.inbox"),
-          path: ROUTES.INBOX,
-          icon: BellIcon,
-          active: location.pathname === ROUTES.INBOX,
-          count: unreadCount,
+          active: routeKind === "attachments",
        },
      ]
    : [
@ -539,7 +527,13 @@ const GlobalNavigation = () => {
          active: routeKind === "explore" || routeKind === "profile" || routeKind === "memo",
          alwaysExpanded: true,
        },
-        { id: "about", label: t("common.about"), path: ROUTES.ABOUT, icon: InfoIcon, active: location.pathname === ROUTES.ABOUT },
+        {
+          id: "about",
+          label: t("common.about"),
+          path: ROUTES.ABOUT,
+          icon: InfoIcon,
+          active: Boolean(matchPath(ROUTES.ABOUT, location.pathname)),
+        },
      ];

  const scopeMenuContent = (
@ -645,21 +639,66 @@ const GlobalNavigation = () => {
  );
 };

-/** The sidebar/header brand slot: the Space switcher when signed in, the plain logo otherwise. */
+/** The sidebar/header brand slot: collection scope on collection routes, instance brand elsewhere. */
 const SidebarBrand = ({ className }: { className?: string }) => {
  const currentUser = useCurrentUser();
+  const location = useLocation();

-  if (currentUser) {
+  if (currentUser && routeSupportsCollectionScope(location.pathname)) {
    return <SpaceSwitcher className={className} />;
  }

  return (
-    <Link to={ROUTES.EXPLORE} className={cn("min-w-0 rounded-md focus-visible:outline-none", className)}>
+    <Link to={currentUser ? ROUTES.HOME : ROUTES.EXPLORE} className={cn("min-w-0 rounded-md focus-visible:outline-none", className)}>
      <MemosLogo compact />
    </Link>
  );
 };

+const InboxFooterLink = () => {
+  const t = useTranslate();
+  const location = useLocation();
+  const { setMobileOpen } = useAppSidebar();
+  const { data: notifications = [] } = useNotifications();
+  const unreadCount = notifications.filter((notification) => notification.status === UserNotification_Status.UNREAD).length;
+  const active = getSidebarRouteKind(location.pathname) === "inbox";
+  const accessibleLabel = unreadCount > 0 ? `${t("common.inbox")}, ${unreadCount} ${t("inbox.unread")}` : t("common.inbox");
+
+  return (
+    <TooltipProvider>
+      <Tooltip>
+        <TooltipTrigger
+          render={
+            <Link
+              to={ROUTES.INBOX}
+              onClick={() => setMobileOpen(false)}
+              aria-label={accessibleLabel}
+              aria-current={active ? "page" : undefined}
+              className={cn(
+                "flex size-9 shrink-0 items-center justify-center rounded-md text-muted-foreground transition-colors hover:bg-sidebar-accent/65 hover:text-foreground md:size-8",
+                SIDEBAR_ROW_FOCUS_CLASSES,
+                active && "bg-sidebar-accent text-sidebar-accent-foreground",
+              )}
+            />
+          }
+        >
+          <span className="relative flex">
+            <BellIcon className="size-4" strokeWidth={1.8} />
+            {unreadCount > 0 && (
+              <span
+                aria-hidden="true"
+                data-inbox-unread-indicator
+                className="absolute -end-0.5 -top-0.5 size-1.5 rounded-full bg-primary ring-2 ring-sidebar"
+              />
+            )}
+          </span>
+        </TooltipTrigger>
+        <TooltipContent side="top">{accessibleLabel}</TooltipContent>
+      </Tooltip>
+    </TooltipProvider>
+  );
+};
+
 const AppSidebar = ({ className }: { className?: string }) => {
  const t = useTranslate();
  const currentUser = useCurrentUser();
@ -692,7 +731,12 @@ const AppSidebar = ({ className }: { className?: string }) => {
      </div>
      <footer className="shrink-0 border-t border-border/70">
        {currentUser ? (
-          <UserMenu />
+          <div className="flex h-10 min-w-0 items-center pe-1">
+            <div className="min-w-0 flex-1">
+              <UserMenu />
+            </div>
+            <InboxFooterLink />
+          </div>
        ) : (
          <Link
            to={ROUTES.AUTH}
--- a/web/src/components/AppSidebar/QuickFindDialog.tsx
+++ b/web/src/components/AppSidebar/QuickFindDialog.tsx
@ -6,13 +6,12 @@ import { Dialog, DialogContent, DialogDescription, DialogTitle } from "@/compone
 import { Input } from "@/components/ui/input";
 import { useAppSidebar } from "@/contexts/AppSidebarContext";
 import { type MemoFilter, replaceFiltersByFactor, stringifyFilters, useMemoFilterContext } from "@/contexts/MemoFilterContext";
+import { useSpaceContext } from "@/contexts/SpaceContext";
 import useCurrentUser from "@/hooks/useCurrentUser";
 import { useMemoViews } from "@/hooks/useUserQueries";
 import { BUILTIN_TASKS_VIEW_ID, getMemoViewId, isMemoScopeRoute } from "@/lib/memo-views";
-import { ROUTES } from "@/router/routes";
 import { useTranslate } from "@/utils/i18n";
-
-export const isQuickFindCollectionRoute = (pathname: string) => isMemoScopeRoute(pathname) || pathname.startsWith("/u/");
+import { getRouteActionPolicy, getSidebarRouteKind } from "./routes";

 export const buildQuickFindFilters = (query: string, currentFilters: MemoFilter[], preserveCurrentScope: boolean): MemoFilter[] => {
  const words = Array.from(new Set(query.trim().split(/\s+/).filter(Boolean)));
@ -20,10 +19,32 @@ export const buildQuickFindFilters = (query: string, currentFilters: MemoFilter[
  return preserveCurrentScope ? replaceFiltersByFactor(currentFilters, "contentSearch", contentFilters) : contentFilters;
 };

+export interface QuickFindSubmission {
+  filters: MemoFilter[];
+  destination?: string;
+  switchToAll: boolean;
+}
+
+export const resolveQuickFindSubmission = (pathname: string, query: string, currentFilters: MemoFilter[]): QuickFindSubmission => {
+  const routePolicy = getRouteActionPolicy(pathname);
+  const filters = buildQuickFindFilters(query, currentFilters, routePolicy.searchScope !== "all");
+  const filterQuery = stringifyFilters(filters);
+  return {
+    filters,
+    destination: routePolicy.searchDestination
+      ? filterQuery
+        ? `${routePolicy.searchDestination}?filter=${filterQuery}`
+        : routePolicy.searchDestination
+      : undefined,
+    switchToAll: routePolicy.searchScope === "all",
+  };
+};
+
 const getScopeLabel = (pathname: string, t: ReturnType<typeof useTranslate>) => {
-  if (pathname === ROUTES.ARCHIVED) return t("common.archived");
-  if (pathname === ROUTES.EXPLORE) return t("common.explore");
-  if (pathname.startsWith("/u/")) return t("common.profile");
+  const routeKind = getSidebarRouteKind(pathname);
+  if (routeKind === "archived") return t("common.archived");
+  if (routeKind === "explore") return t("common.explore");
+  if (routeKind === "profile") return t("common.profile");
  return t("common.memos");
 };

@ -34,13 +55,18 @@ const QuickFindDialog = () => {
  const currentUser = useCurrentUser();
  const { data: memoViews = [] } = useMemoViews(currentUser?.name);
  const { filters, setFilters, setMemoView, memoView } = useMemoFilterContext();
+  const { clearSelectedSpace, selectedSpace, selectedSpaceName } = useSpaceContext();
  const { quickFindOpen, setQuickFindOpen } = useAppSidebar();
  const [query, setQuery] = useState("");
-  const collectionRoute = isQuickFindCollectionRoute(location.pathname);
  const viewApplies = isMemoScopeRoute(location.pathname);
  const selectedMemoView = viewApplies ? memoViews.find((item) => getMemoViewId(item.name) === memoView) : undefined;
-  const scopeLabel =
+  const lensLabel =
    viewApplies && memoView === BUILTIN_TASKS_VIEW_ID ? t("common.tasks") : selectedMemoView?.title || getScopeLabel(location.pathname, t);
+  const routePolicy = getRouteActionPolicy(location.pathname);
+  const scopeLabel =
+    routePolicy.searchScope === "remembered-collection" && selectedSpaceName
+      ? `${selectedSpace?.title || t("space.current")} · ${lensLabel}`
+      : lensLabel;

  useEffect(() => {
    if (!quickFindOpen) return;
@ -53,15 +79,19 @@ const QuickFindDialog = () => {
  }, [filters, quickFindOpen]);

  const submitQuery = () => {
-    const nextFilters = buildQuickFindFilters(query, filters, collectionRoute);
+    const submission = resolveQuickFindSubmission(location.pathname, query, filters);

-    if (collectionRoute) {
-      setFilters(nextFilters);
-    } else {
-      const filterQuery = stringifyFilters(nextFilters);
-      setFilters(nextFilters);
+    if (submission.switchToAll) {
+      // This is an explicit cross-Space action, so switch the collection state
+      // to All without inserting an intermediate Home history entry.
+      clearSelectedSpace();
+    }
+
+    setFilters(submission.filters);
+
+    if (submission.destination) {
      setMemoView(undefined);
-      navigate(filterQuery ? `${ROUTES.HOME}?filter=${filterQuery}` : ROUTES.HOME);
+      navigate(submission.destination);
    }

    setQuickFindOpen(false);
--- a/web/src/components/AppSidebar/routes.ts
+++ b/web/src/components/AppSidebar/routes.ts
@ -4,13 +4,69 @@ import { ROUTES } from "@/router/routes";

 export type SidebarRouteKind = MemoScope | "profile" | "views" | "attachments" | "inbox" | "settings" | "memo" | "empty";

+export type RouteSearchScope = "remembered-collection" | "profile" | "all";
+export type RouteComposePlacement = "remembered-space" | "unassigned";
+
+export interface RouteActionPolicy {
+  searchScope: RouteSearchScope;
+  /** When absent, Quick Find stays on the current route. */
+  searchDestination?: string;
+  composePlacement: RouteComposePlacement;
+}
+
 export const getSidebarRouteKind = (path: string): SidebarRouteKind => {
-  if (isMemoScopeRoute(path)) return resolveMemoScope(path);
-  if (matchPath("/u/:username", path)) return "profile";
-  if (path === ROUTES.VIEWS) return "views";
-  if (path === ROUTES.ATTACHMENTS) return "attachments";
-  if (path === ROUTES.INBOX) return "inbox";
-  if (path === ROUTES.SETTING) return "settings";
-  if (matchPath("/memos/:uid", path) || matchPath(`${ROUTES.SHARED_MEMO}/:token`, path)) return "memo";
+  const normalizedPath = path.length > 1 ? path.replace(/\/+$/, "") : path;
+  if (isMemoScopeRoute(normalizedPath)) return resolveMemoScope(normalizedPath);
+  if (matchPath("/u/:username", normalizedPath)) return "profile";
+  if (matchPath(ROUTES.VIEWS, normalizedPath)) return "views";
+  if (matchPath(ROUTES.ATTACHMENTS, normalizedPath)) return "attachments";
+  if (matchPath(ROUTES.INBOX, normalizedPath)) return "inbox";
+  if (matchPath(ROUTES.SETTING, normalizedPath)) return "settings";
+  if (matchPath("/memos/:uid", normalizedPath) || matchPath(`${ROUTES.SHARED_MEMO}/:token`, normalizedPath)) return "memo";
  return "empty";
 };
+
+/** Routes whose collections are filtered by the remembered All / Space scope. */
+export const routeSupportsCollectionScope = (path: string): boolean => {
+  const kind = getSidebarRouteKind(path);
+  return kind === "home" || kind === "explore" || kind === "archived" || kind === "attachments";
+};
+
+/**
+ * Keeps read/search scope and write placement explicit at route boundaries.
+ * A remembered Space is ambient collection state, so global and canonical
+ * resource routes must not silently use it as a creation target.
+ */
+export const getRouteActionPolicy = (path: string): RouteActionPolicy => {
+  const kind = getSidebarRouteKind(path);
+
+  if (kind === "home" || kind === "explore" || kind === "archived") {
+    return {
+      searchScope: "remembered-collection",
+      composePlacement: "remembered-space",
+    };
+  }
+
+  if (kind === "attachments") {
+    return {
+      searchScope: "remembered-collection",
+      searchDestination: ROUTES.HOME,
+      composePlacement: "remembered-space",
+    };
+  }
+
+  if (kind === "profile") {
+    return {
+      searchScope: "profile",
+      // Re-enter the memo list tab on the same profile (dropping ?view=map).
+      searchDestination: path.length > 1 ? path.replace(/\/+$/, "") : path,
+      composePlacement: "unassigned",
+    };
+  }
+
+  return {
+    searchScope: "all",
+    searchDestination: ROUTES.HOME,
+    composePlacement: "unassigned",
+  };
+};
--- a/web/src/components/AttachmentLibrary/AttachmentLibraryPrimitives.tsx
+++ b/web/src/components/AttachmentLibrary/AttachmentLibraryPrimitives.tsx
@ -1,8 +1,10 @@
 import { ExternalLinkIcon } from "lucide-react";
 import { Link } from "react-router-dom";
+import { createMemoNavigationState } from "@/components/MemoView/navigation";
 import { Badge } from "@/components/ui/badge";
 import { Button } from "@/components/ui/button";
 import { cn } from "@/lib/utils";
+import { ROUTES } from "@/router/routes";
 import { useTranslate } from "@/utils/i18n";

 interface AttachmentMetadataLineProps {
@ -61,6 +63,9 @@ export const AttachmentSourceChip = ({
  return (
    <Link
      to={`/${memoName}`}
+      // Attachments is collection-scoped, but Memo filters render on Home.
+      // Carry a Home origin so direct-resource handling preserves this scope.
+      state={createMemoNavigationState(ROUTES.HOME, "preserve")}
      className="inline-flex max-w-full items-center truncate rounded-full border border-border/60 bg-muted/30 px-1.5 py-0.5 text-[11px] text-muted-foreground hover:bg-muted/50"
    >
      <span className="truncate">{t("attachment-library.labels.memo")}</span>
--- a/web/src/components/Inbox/MemoCommentMessage.tsx
+++ b/web/src/components/Inbox/MemoCommentMessage.tsx
@ -133,9 +133,10 @@ function MemoCommentMessage({ notification }: Props) {
            </p>
          </div>

-          <div
+          <button
+            type="button"
            onClick={handleNavigateToMemo}
-            className="p-2 sm:p-3 rounded-lg bg-gradient-to-br from-primary/[0.06] to-primary/[0.03] hover:from-primary/[0.1] hover:to-primary/[0.06] cursor-pointer border border-primary/30 hover:border-primary/50 transition-all duration-200 group/comment shadow-sm hover:shadow"
+            className="w-full p-2 text-left sm:p-3 rounded-lg bg-gradient-to-br from-primary/[0.06] to-primary/[0.03] hover:from-primary/[0.1] hover:to-primary/[0.06] cursor-pointer border border-primary/30 hover:border-primary/50 transition-all duration-200 group/comment shadow-sm hover:shadow"
          >
            <div className="flex items-start gap-2">
              <div className="w-5 h-5 flex items-center justify-center shrink-0">
@ -148,7 +149,7 @@ function MemoCommentMessage({ notification }: Props) {
                </p>
              </div>
            </div>
-          </div>
+          </button>
        </div>
      </div>
    </div>
--- a/web/src/components/Inbox/MemoMentionMessage.tsx
+++ b/web/src/components/Inbox/MemoMentionMessage.tsx
@ -137,9 +137,10 @@ function MemoMentionMessage({ notification }: Props) {
            </div>
          )}

-          <div
+          <button
+            type="button"
            onClick={handleNavigate}
-            className="p-2 sm:p-3 rounded-lg bg-gradient-to-br from-primary/[0.06] to-primary/[0.03] hover:from-primary/[0.1] hover:to-primary/[0.06] cursor-pointer border border-primary/30 hover:border-primary/50 transition-all duration-200 group/comment shadow-sm hover:shadow"
+            className="w-full p-2 text-left sm:p-3 rounded-lg bg-gradient-to-br from-primary/[0.06] to-primary/[0.03] hover:from-primary/[0.1] hover:to-primary/[0.06] cursor-pointer border border-primary/30 hover:border-primary/50 transition-all duration-200 group/comment shadow-sm hover:shadow"
          >
            <div className="flex items-start gap-2">
              <div className="w-5 h-5 flex items-center justify-center shrink-0">
@ -154,7 +155,7 @@ function MemoMentionMessage({ notification }: Props) {
                </p>
              </div>
            </div>
-          </div>
+          </button>
        </div>
      </div>
    </div>
--- a/web/src/components/MemoActionMenu/MemoActionMenu.tsx
+++ b/web/src/components/MemoActionMenu/MemoActionMenu.tsx
@ -56,6 +56,7 @@ const MemoActionMenu = (props: MemoActionMenuProps) => {
    confirmDeleteMemo,
  } = useMemoActionHandlers({
    memo,
+    parentScope: props.parentScope,
    onEdit: props.onEdit,
    setDeleteDialogOpen,
  });
--- a/web/src/components/MemoActionMenu/hooks.ts
+++ b/web/src/components/MemoActionMenu/hooks.ts
@ -4,6 +4,7 @@ import { useCallback } from "react";
 import toast from "react-hot-toast";
 import { useLocation } from "react-router-dom";
 import { useInstance } from "@/contexts/InstanceContext";
+import { useSpaceContext } from "@/contexts/SpaceContext";
 import { memoKeys, useDeleteMemo, useUpdateMemo } from "@/hooks/useMemoQueries";
 import useNavigateTo from "@/hooks/useNavigateTo";
 import { userKeys } from "@/hooks/useUserQueries";
@ -13,22 +14,25 @@ import { State } from "@/types/proto/api/v1/common_pb";
 import type { Memo } from "@/types/proto/api/v1/memo_service_pb";
 import { useTranslate } from "@/utils/i18n";
 import { checkAllTasks, uncheckAllTasks } from "@/utils/markdown-task-actions";
+import { isMemoDetailPath, type MemoOriginScope } from "../MemoView/navigation";

 interface UseMemoActionHandlersOptions {
  memo: Memo;
+  parentScope: MemoOriginScope;
  onEdit?: () => void;
  setDeleteDialogOpen: (open: boolean) => void;
 }

-export const useMemoActionHandlers = ({ memo, onEdit, setDeleteDialogOpen }: UseMemoActionHandlersOptions) => {
+export const useMemoActionHandlers = ({ memo, parentScope, onEdit, setDeleteDialogOpen }: UseMemoActionHandlersOptions) => {
  const t = useTranslate();
  const location = useLocation();
  const navigateTo = useNavigateTo();
  const queryClient = useQueryClient();
  const { profile } = useInstance();
+  const { clearSelectedSpace } = useSpaceContext();
  const { mutateAsync: updateMemo } = useUpdateMemo();
  const { mutateAsync: deleteMemo } = useDeleteMemo();
-  const isInMemoDetailPage = location.pathname.startsWith(`/${memo.name}`);
+  const isInMemoDetailPage = isMemoDetailPath(location.pathname, memo.name);

  const memoUpdatedCallback = useCallback(() => {
    // Invalidate user stats to trigger refetch
@ -101,10 +105,13 @@ export const useMemoActionHandlers = ({ memo, onEdit, setDeleteDialogOpen }: Use
    }

    if (isInMemoDetailPage) {
+      if (parentScope === "all") {
+        clearSelectedSpace();
+      }
      navigateTo(memo.state === State.ARCHIVED ? ROUTES.HOME : ROUTES.ARCHIVED);
    }
    memoUpdatedCallback();
-  }, [memo.name, memo.state, t, isInMemoDetailPage, navigateTo, memoUpdatedCallback, updateMemo]);
+  }, [memo.name, memo.state, t, isInMemoDetailPage, parentScope, clearSelectedSpace, navigateTo, memoUpdatedCallback, updateMemo]);

  const handleCopyLink = useCallback(() => {
    let host = profile.instanceUrl;
@ -144,10 +151,24 @@ export const useMemoActionHandlers = ({ memo, onEdit, setDeleteDialogOpen }: Use
      queryClient.invalidateQueries({ queryKey: memoKeys.comments(memo.parent) });
    }
    if (isInMemoDetailPage) {
+      if (parentScope === "all") {
+        clearSelectedSpace();
+      }
      navigateTo(ROUTES.HOME);
    }
    memoUpdatedCallback();
-  }, [memo.name, memo.parent, t, isInMemoDetailPage, navigateTo, memoUpdatedCallback, deleteMemo, queryClient]);
+  }, [
+    memo.name,
+    memo.parent,
+    t,
+    isInMemoDetailPage,
+    parentScope,
+    clearSelectedSpace,
+    navigateTo,
+    memoUpdatedCallback,
+    deleteMemo,
+    queryClient,
+  ]);

  return {
    handleTogglePinMemoBtnClick,
--- a/web/src/components/MemoActionMenu/types.ts
+++ b/web/src/components/MemoActionMenu/types.ts
@ -1,7 +1,9 @@
 import type { Memo } from "@/types/proto/api/v1/memo_service_pb";
+import type { MemoOriginScope } from "../MemoView/navigation";

 export interface MemoActionMenuProps {
  memo: Memo;
+  parentScope: MemoOriginScope;
  readonly?: boolean;
  className?: string;
  onEdit?: () => void;
--- a/web/src/components/MemoCommentSection.tsx
+++ b/web/src/components/MemoCommentSection.tsx
@ -3,6 +3,7 @@ import { type ComponentType, useCallback, useState } from "react";
 import { loadMemoEditor } from "@/components/MemoEditor/loader";
 import type { MemoEditorProps } from "@/components/MemoEditor/types";
 import MemoView from "@/components/MemoView";
+import type { MemoOriginScope } from "@/components/MemoView/navigation";
 import { Button } from "@/components/ui/button";
 import useCurrentUser from "@/hooks/useCurrentUser";
 import { extractMemoIdFromName } from "@/lib/resource-names";
@ -13,12 +14,21 @@ interface Props {
  memo: Memo;
  comments: Memo[];
  parentPage?: string;
+  parentScope?: MemoOriginScope;
  hasMoreComments?: boolean;
  isFetchingMoreComments?: boolean;
  onLoadMoreComments?: () => void;
 }

-const MemoCommentSection = ({ memo, comments, parentPage, hasMoreComments, isFetchingMoreComments, onLoadMoreComments }: Props) => {
+const MemoCommentSection = ({
+  memo,
+  comments,
+  parentPage,
+  parentScope,
+  hasMoreComments,
+  isFetchingMoreComments,
+  onLoadMoreComments,
+}: Props) => {
  const t = useTranslate();
  const currentUser = useCurrentUser();
  const [showEditor, setShowEditor] = useState(false);
@ -113,7 +123,7 @@ const MemoCommentSection = ({ memo, comments, parentPage, hasMoreComments, isFet
        )}
        {comments.map((comment) => (
          <div className="w-full" key={comment.name} id={extractMemoIdFromName(comment.name)}>
-            <MemoView memo={comment} parentPage={parentPage} showCreator compact />
+            <MemoView memo={comment} parentPage={parentPage} parentScope={parentScope} showCreator showSpace compact />
          </div>
        ))}
        {hasMoreComments && (
--- a/web/src/components/MemoContent/MemoMarkdownRenderer.tsx
+++ b/web/src/components/MemoContent/MemoMarkdownRenderer.tsx
@ -7,6 +7,7 @@ import { isMentionElement, isTagElement, isTaskListItemElement } from "@/types/m
 import type { Attachment } from "@/types/proto/api/v1/attachment_service_pb";
 import { lazyWithReload } from "@/utils/lazy";
 import { resolveManagedAttachmentImageSource } from "@/utils/managed-attachment";
+import type { MemoOriginScope } from "../MemoView/navigation";
 import { CodeBlock } from "./CodeBlock";
 import { MarkdownRenderContext, rootMarkdownRenderContext } from "./MarkdownRenderContext";
 import { Mention } from "./Mention";
@ -23,6 +24,9 @@ export interface MemoMarkdownRendererProps {
  resolvedMentionUsernames: Set<string>;
  /** Resource name of the memo (e.g. `memos/abc123`), used to target footnote links at the detail page. */
  memoName?: string;
+  /** Collection page that opened the memo detail. */
+  parentPage?: string;
+  parentScope?: MemoOriginScope;
  /** Whether the memo is rendered as a collapsed feed card. */
  compact?: boolean;
 }
@ -62,6 +66,8 @@ export const MemoMarkdownRendererCore = ({
  attachments = [],
  resolvedMentionUsernames,
  memoName,
+  parentPage,
+  parentScope,
  compact,
  mathRemarkPlugins = [],
  mathRehypePlugins = [],
@ -128,7 +134,7 @@ export const MemoMarkdownRendererCore = ({
      // than opening a new tab; everything else is treated as an external link.
      if (typeof href === "string" && href.startsWith("#")) {
        return (
-          <AnchorLink href={href} memoName={memoName} compact={compact} {...props}>
+          <AnchorLink href={href} memoName={memoName} parentPage={parentPage} parentScope={parentScope} compact={compact} {...props}>
            {children}
          </AnchorLink>
        );
@ -188,6 +194,8 @@ export const MemoMarkdownRenderer = memo(
    previous.content === next.content &&
    previous.attachments === next.attachments &&
    previous.memoName === next.memoName &&
+    previous.parentPage === next.parentPage &&
+    previous.parentScope === next.parentScope &&
    previous.compact === next.compact &&
    haveEqualResolvedMentions(previous.resolvedMentionUsernames, next.resolvedMentionUsernames),
 );
--- a/web/src/components/MemoContent/Tag.tsx
+++ b/web/src/components/MemoContent/Tag.tsx
@ -2,6 +2,7 @@ import type { Element } from "hast";
 import { useLocation } from "react-router-dom";
 import { useAuth } from "@/contexts/AuthContext";
 import { type MemoFilter, stringifyFilters, useMemoFilterContext } from "@/contexts/MemoFilterContext";
+import { useSpaceContext } from "@/contexts/SpaceContext";
 import useNavigateTo from "@/hooks/useNavigateTo";
 import { colorToHex } from "@/lib/color";
 import { tagStyles } from "@/lib/markdownStyles";
@ -9,6 +10,7 @@ import { findTagMetadata } from "@/lib/tag";
 import { cn } from "@/lib/utils";
 import { Routes } from "@/router";
 import { useMemoViewContext } from "../MemoView/MemoViewContext";
+import { isMemoCollectionOrigin, isMemoResourcePath, withMemoFilter } from "../MemoView/navigation";

 interface TagProps extends React.HTMLAttributes<HTMLSpanElement> {
  node?: Element; // AST node from react-markdown
@ -17,9 +19,10 @@ interface TagProps extends React.HTMLAttributes<HTMLSpanElement> {
 }

 export const Tag: React.FC<TagProps> = ({ "data-tag": dataTag, children, className, style, node: _node, ...props }) => {
-  const { parentPage } = useMemoViewContext();
+  const { parentPage, parentScope } = useMemoViewContext();
  const location = useLocation();
  const navigateTo = useNavigateTo();
+  const { clearSelectedSpace } = useSpaceContext();
  const { getFiltersByFactor, removeFilter, addFilter } = useMemoFilterContext();
  const { userTagsSetting } = useAuth();

@ -43,12 +46,11 @@ export const Tag: React.FC<TagProps> = ({ "data-tag": dataTag, children, classNa
    e.stopPropagation();

    // If the tag is clicked in a memo detail page, we should navigate to the memo list page.
-    if (location.pathname.startsWith("/m")) {
-      const pathname = parentPage || Routes.HOME;
-      const searchParams = new URLSearchParams();
-
-      searchParams.set("filter", stringifyFilters([{ factor: "tagSearch", value: tag }]));
-      navigateTo(`${pathname}?${searchParams.toString()}`);
+    if (isMemoResourcePath(location.pathname)) {
+      if (parentScope === "all" && isMemoCollectionOrigin(parentPage)) {
+        clearSelectedSpace();
+      }
+      navigateTo(withMemoFilter(parentPage || Routes.HOME, stringifyFilters([{ factor: "tagSearch", value: tag }])));
      return;
    }

--- a/web/src/components/MemoContent/index.tsx
+++ b/web/src/components/MemoContent/index.tsx
@ -39,6 +39,8 @@ const MemoContent = (props: MemoContentProps) => {
          attachments={attachments}
          resolvedMentionUsernames={resolvedMentionUsernames}
          memoName={props.memoName}
+          parentPage={props.parentPage}
+          parentScope={props.parentScope}
          compact={Boolean(props.compact)}
        />
      </div>
--- a/web/src/components/MemoContent/markdown/AnchorLink.tsx
+++ b/web/src/components/MemoContent/markdown/AnchorLink.tsx
@ -2,12 +2,16 @@ import { Link } from "react-router-dom";
 import { markdownStyles } from "@/lib/markdownStyles";
 import { cn } from "@/lib/utils";
 import { findAnchorTarget } from "@/utils/markdown-manipulation";
+import { createMemoNavigationState, type MemoOriginScope } from "../../MemoView/navigation";
 import type { ReactMarkdownProps } from "./types";

 interface AnchorLinkProps extends React.AnchorHTMLAttributes<HTMLAnchorElement>, ReactMarkdownProps {
  href: string;
  /** Resource name of the enclosing memo (e.g. `memos/abc123`), when known. */
  memoName?: string;
+  /** Collection page that rendered the enclosing memo. */
+  parentPage?: string;
+  parentScope?: MemoOriginScope;
  /** Whether the memo is rendered as a collapsed feed card. */
  compact?: boolean;
  children: React.ReactNode;
@ -22,7 +26,17 @@ interface AnchorLinkProps extends React.AnchorHTMLAttributes<HTMLAnchorElement>,
 * below the fold, so we fall back to navigating to the memo detail page (with the hash), where
 * MemoDetail scrolls the target into view.
 */
-export const AnchorLink = ({ href, memoName, compact, children, className, node: _node, ...props }: AnchorLinkProps) => {
+export const AnchorLink = ({
+  href,
+  memoName,
+  parentPage,
+  parentScope,
+  compact,
+  children,
+  className,
+  node: _node,
+  ...props
+}: AnchorLinkProps) => {
  const handleClick = (event: React.MouseEvent<HTMLAnchorElement>) => {
    if (compact) return; // Let the link navigate to the detail page.
    const id = decodeURIComponent(href.slice(1));
@ -41,7 +55,13 @@ export const AnchorLink = ({ href, memoName, compact, children, className, node:

  if (memoName) {
    return (
-      <Link to={`/${memoName}${href}`} onClick={handleClick} className={classes} {...props}>
+      <Link
+        to={`/${memoName}${href}`}
+        state={parentPage && parentScope ? createMemoNavigationState(parentPage, parentScope) : undefined}
+        onClick={handleClick}
+        className={classes}
+        {...props}
+      >
        {children}
      </Link>
    );
--- a/web/src/components/MemoContent/types.ts
+++ b/web/src/components/MemoContent/types.ts
@ -1,5 +1,6 @@
 import type React from "react";
 import type { Attachment } from "@/types/proto/api/v1/attachment_service_pb";
+import type { MemoOriginScope } from "../MemoView/navigation";

 export interface MemoContentProps {
  content: string;
@ -7,6 +8,9 @@ export interface MemoContentProps {
  attachments?: Attachment[];
  /** Resource name of the memo (e.g. `memos/abc123`). Enables footnote links to target the memo detail page. */
  memoName?: string;
+  /** Collection page that rendered the memo, preserved when an inline link opens its detail page. */
+  parentPage?: string;
+  parentScope?: MemoOriginScope;
  /** The card renders collapsed (ClampedSection), so footnote links navigate instead of scrolling. */
  compact?: boolean;
  className?: string;
--- a/web/src/components/MemoDetailSidebar/MemoDetailSidebar.tsx
+++ b/web/src/components/MemoDetailSidebar/MemoDetailSidebar.tsx
@ -8,6 +8,7 @@ import SidebarSection, { SIDEBAR_SECTION_STACK_CLASSES } from "@/components/AppS
 import { extractHeadings } from "@/components/MemoContent/pipeline";
 import { getRelationBuckets, getRelationMemo } from "@/components/MemoMetadata/Relation/relationHelpers";
 import { useResolvedRelationMemos } from "@/components/MemoMetadata/Relation/useResolvedRelationMemos";
+import { createMemoNavigationState, type MemoOriginScope } from "@/components/MemoView/navigation";
 import { DropdownMenu, DropdownMenuContent, DropdownMenuItem, DropdownMenuTrigger } from "@/components/ui/dropdown-menu";
 import { useInstance } from "@/contexts/InstanceContext";
 import { useOverflowTitle } from "@/hooks";
@ -23,12 +24,24 @@ import MemoSharePanel from "./MemoSharePanel";

 interface Props {
  memo: Memo;
+  parentPage?: string;
+  parentScope?: MemoOriginScope;
  className?: string;
  onShareImageOpen?: () => void;
  forceReadonly?: boolean;
 }

-const BacklinkRow = ({ relation, snippet }: { relation: MemoRelation; snippet: string }) => {
+const BacklinkRow = ({
+  relation,
+  snippet,
+  parentPage,
+  parentScope,
+}: {
+  relation: MemoRelation;
+  snippet: string;
+  parentPage?: string;
+  parentScope?: MemoOriginScope;
+}) => {
  const { ref, title } = useOverflowTitle<HTMLSpanElement>(snippet);
  const relatedMemo = getRelationMemo(relation, "referenced");
  if (!relatedMemo) {
@ -39,6 +52,7 @@ const BacklinkRow = ({ relation, snippet }: { relation: MemoRelation; snippet: s
    <Link
      className={cn(SIDEBAR_ROW_CLASSES, "text-muted-foreground hover:bg-sidebar-accent/65 hover:text-foreground")}
      to={`/${relatedMemo.name}`}
+      state={parentPage && parentScope ? createMemoNavigationState(parentPage, parentScope) : undefined}
      title={title}
      viewTransition
    >
@ -50,7 +64,7 @@ const BacklinkRow = ({ relation, snippet }: { relation: MemoRelation; snippet: s
  );
 };

-const MemoDetailSidebar = ({ memo, className, onShareImageOpen, forceReadonly = false }: Props) => {
+const MemoDetailSidebar = ({ memo, parentPage, parentScope, className, onShareImageOpen, forceReadonly = false }: Props) => {
  const t = useTranslate();
  const currentUser = useCurrentUser();
  const { profile } = useInstance();
@ -146,7 +160,15 @@ const MemoDetailSidebar = ({ memo, className, onShareImageOpen, forceReadonly =
        <SidebarSection label={t("common.referenced-by")}>
          {referenced.map((relation) => {
            const relatedMemo = getRelationMemo(relation, "referenced");
-            return <BacklinkRow key={`referenced-${relatedMemo?.name}`} relation={relation} snippet={backlinkSnippet(relation)} />;
+            return (
+              <BacklinkRow
+                key={`referenced-${relatedMemo?.name}`}
+                relation={relation}
+                snippet={backlinkSnippet(relation)}
+                parentPage={parentPage}
+                parentScope={parentScope}
+              />
+            );
          })}
        </SidebarSection>
      )}
--- a/web/src/components/MemoEditor/Toolbar/EditorToolbar.tsx
+++ b/web/src/components/MemoEditor/Toolbar/EditorToolbar.tsx
@ -13,6 +13,7 @@ export const EditorToolbar: FC<EditorToolbarProps> = ({
  onSave,
  onCancel,
  memoName,
+  space,
  onAudioRecorderClick,
  viewToggles,
  onInsertImages,
@ -56,7 +57,7 @@ export const EditorToolbar: FC<EditorToolbarProps> = ({
          viewToggles={viewToggles}
          onInsertImages={onInsertImages}
        />
-        <VisibilitySelector value={visibility} onChange={handleVisibilityChange} />
+        <VisibilitySelector value={visibility} space={space} onChange={handleVisibilityChange} />
      </div>

      <div className="flex flex-row justify-end items-center gap-2">
--- a/web/src/components/MemoEditor/Toolbar/VisibilitySelector.tsx
+++ b/web/src/components/MemoEditor/Toolbar/VisibilitySelector.tsx
@ -1,7 +1,6 @@
 import { CheckIcon, ChevronDownIcon } from "lucide-react";
 import { DropdownMenu, DropdownMenuContent, DropdownMenuItem, DropdownMenuTrigger } from "@/components/ui/dropdown-menu";
 import VisibilityIcon from "@/components/VisibilityIcon";
-import { useSpaceContext } from "@/contexts/SpaceContext";
 import { cn } from "@/lib/utils";
 import { useTranslate } from "@/utils/i18n";
 import { getAssignableVisibilityOptions, getVisibilityOption } from "@/utils/memo";
@ -11,9 +10,8 @@ const VisibilitySelector = (props: VisibilitySelectorProps) => {
  const { value, onChange } = props;
  const compact = props.size === "compact";
  const t = useTranslate();
-  const { selectedSpaceName } = useSpaceContext();

-  const visibilityOptions = getAssignableVisibilityOptions({ spaceSelected: Boolean(selectedSpaceName), current: value });
+  const visibilityOptions = getAssignableVisibilityOptions({ hasSpacePlacement: Boolean(props.space), current: value });
  // Resolved from the full catalog, so the trigger names the memo's audience even
  // when that audience is not currently on offer.
  const currentOption = getVisibilityOption(value);
--- a/web/src/components/MemoEditor/index.tsx
+++ b/web/src/components/MemoEditor/index.tsx
@ -72,6 +72,9 @@ const MemoEditorImpl: React.FC<MemoEditorProps> = ({
  const [isFormattingToolbarVisible, setFormattingToolbarVisible] = useLocalStorage(FORMATTING_TOOLBAR_STORAGE_KEY, false);

  const memoName = memo?.name;
+  // Existing resources own their placement. New replies are not placed
+  // independently; only a new top-level memo inherits its host's target.
+  const editorSpace = memo ? memo.space : parentMemoName ? undefined : defaultSpace;
  const canTranscribe = useMemo(() => {
    const providerId = aiSetting.transcription?.providerId ?? "";
    if (!providerId) return false;
@ -362,6 +365,7 @@ const MemoEditorImpl: React.FC<MemoEditorProps> = ({
            onSave={handleSave}
            onCancel={onCancel ? handleCancel : undefined}
            memoName={memoName}
+            space={editorSpace}
            onAudioRecorderClick={handleAudioRecorderClick}
            viewToggles={viewToggles}
            onInsertImages={handleInsertImages}
--- a/web/src/components/MemoEditor/types/components.ts
+++ b/web/src/components/MemoEditor/types/components.ts
@ -57,6 +57,8 @@ export interface EditorToolbarProps {
  onSave: () => void;
  onCancel?: () => void;
  memoName?: string;
+  /** The Space that owns the memo being created or edited, if any. */
+  space?: string;
  onAudioRecorderClick: () => void;
  viewToggles?: EditorViewToggles;
  onInsertImages: (files: File[]) => void;
@ -105,6 +107,8 @@ export interface InsertMenuProps {
 export interface VisibilitySelectorProps {
  value: Visibility;
  onChange: (visibility: Visibility) => void;
+  /** The memo's actual placement; independent of the ambient collection scope. */
+  space?: string;
  onOpenChange?: (open: boolean) => void;
  /** "compact" renders a 13px trigger that blends into dense surfaces like the memo detail rail. */
  size?: "default" | "compact";
--- a/web/src/components/MemoMetadata/Relation/RelationCard.tsx
+++ b/web/src/components/MemoMetadata/Relation/RelationCard.tsx
@ -1,15 +1,23 @@
 import MemoSnippetLink from "@/components/MemoView/components/MemoSnippetLink";
+import { createMemoNavigationState, type MemoOriginScope } from "@/components/MemoView/navigation";
 import type { MemoRelation_Memo } from "@/types/proto/api/v1/memo_service_pb";

 interface RelationCardProps {
  memo: MemoRelation_Memo;
  parentPage?: string;
+  parentScope?: MemoOriginScope;
  className?: string;
 }

-const RelationCard = ({ memo, parentPage, className }: RelationCardProps) => {
+const RelationCard = ({ memo, parentPage, parentScope, className }: RelationCardProps) => {
  return (
-    <MemoSnippetLink name={memo.name} snippet={memo.snippet} to={`/${memo.name}`} state={{ from: parentPage }} className={className} />
+    <MemoSnippetLink
+      name={memo.name}
+      snippet={memo.snippet}
+      to={`/${memo.name}`}
+      state={parentPage && parentScope ? createMemoNavigationState(parentPage, parentScope) : undefined}
+      className={className}
+    />
  );
 };

--- a/web/src/components/MemoMetadata/Relation/RelationListView.tsx
+++ b/web/src/components/MemoMetadata/Relation/RelationListView.tsx
@ -1,6 +1,7 @@
 import { LinkIcon, MilestoneIcon } from "lucide-react";
 import { useMemo, useState } from "react";
 import MetadataSection from "@/components/MemoMetadata/MetadataSection";
+import type { MemoOriginScope } from "@/components/MemoView/navigation";
 import { useNearViewport } from "@/hooks/useNearViewport";
 import type { MemoRelation } from "@/types/proto/api/v1/memo_service_pb";
 import { useTranslate } from "@/utils/i18n";
@ -12,10 +13,11 @@ interface RelationListViewProps {
  relations: MemoRelation[];
  currentMemoName?: string;
  parentPage?: string;
+  parentScope?: MemoOriginScope;
  className?: string;
 }

-function RelationListView({ relations, currentMemoName, parentPage, className }: RelationListViewProps) {
+function RelationListView({ relations, currentMemoName, parentPage, parentScope, className }: RelationListViewProps) {
  const t = useTranslate();
  const [activeTab, setActiveTab] = useState<"referencing" | "referenced">("referencing");
  const { ref: viewportRef, isNearViewport } = useNearViewport<HTMLDivElement>();
@ -79,7 +81,12 @@ function RelationListView({ relations, currentMemoName, parentPage, className }:
          return null;
        }
        return (
-          <RelationCard key={getRelationMemoName(relation, direction)} memo={resolvedMemos[memo.name] ?? memo} parentPage={parentPage} />
+          <RelationCard
+            key={getRelationMemoName(relation, direction)}
+            memo={resolvedMemos[memo.name] ?? memo}
+            parentPage={parentPage}
+            parentScope={parentScope}
+          />
        );
      })}
    </MetadataSection>
--- a/web/src/components/MemoPreview/MemoPreview.tsx
+++ b/web/src/components/MemoPreview/MemoPreview.tsx
@ -29,6 +29,7 @@ const STUB_CONTEXT: MemoViewContextValue = {
  creator: undefined,
  currentUser: undefined,
  parentPage: "/",
+  parentScope: "all",
  cardWidth: 0,
  isArchived: false,
  readonly: true,
--- a/web/src/components/MemoView/MemoView.tsx
+++ b/web/src/components/MemoView/MemoView.tsx
@ -14,13 +14,24 @@ import { MemoBody, MemoCommentListView, MemoHeader } from "./components";
 import { MEMO_CARD_BASE_CLASSES } from "./constants";
 import { useImagePreview } from "./hooks";
 import { computeCommentAmount, MemoViewContext } from "./MemoViewContext";
+import { isMemoDetailPath, resolveMemoOrigin } from "./navigation";
 import type { MemoViewProps } from "./types";

 const MemoShareImageDialog = lazyWithReload(() => import("../MemoActionMenu/MemoShareImageDialog"));
 const PreviewImageDialog = lazyWithReload(() => import("../PreviewImageDialog"));

 const MemoView: React.FC<MemoViewProps> = (props: MemoViewProps) => {
-  const { memo: memoData, className, parentPage: parentPageProp, compact, showCreator, showVisibility, showPinned } = props;
+  const {
+    memo: memoData,
+    className,
+    parentPage: parentPageProp,
+    parentScope: parentScopeProp,
+    compact,
+    showCreator,
+    showVisibility,
+    showPinned,
+    showSpace,
+  } = props;
  const cardRef = useRef<HTMLDivElement>(null);
  const [showEditor, setShowEditor] = useState(false);
  const [EditorComponent, setEditorComponent] = useState<ComponentType<MemoEditorProps>>();
@ -31,7 +42,14 @@ const MemoView: React.FC<MemoViewProps> = (props: MemoViewProps) => {
  const creator = useResolvedUser(memoData.creator, { enabled: Boolean(showCreator || props.shareImageDialogOpen) });
  const isArchived = memoData.state === State.ARCHIVED;
  const readonly = memoData.creator !== currentUser?.name && !isSuperUser(currentUser);
-  const parentPage = parentPageProp || "/";
+  const location = useLocation();
+  const { parentPage, parentScope } = resolveMemoOrigin({
+    explicitParentPage: parentPageProp,
+    explicitParentScope: parentScopeProp,
+    pathname: location.pathname,
+    search: location.search,
+    memoName: memoData.name,
+  });

  // Blur content when any tag has blur_content enabled in the current user's tag settings.
  const [showBlurredContent, setShowBlurredContent] = useState(false);
@ -50,8 +68,7 @@ const MemoView: React.FC<MemoViewProps> = (props: MemoViewProps) => {
  }, []);
  const closeEditor = useCallback(() => setShowEditor(false), []);

-  const location = useLocation();
-  const isInMemoDetailPage = location.pathname.startsWith(`/${memoData.name}`) || location.pathname.startsWith("/memos/shares/");
+  const isInMemoDetailPage = isMemoDetailPath(location.pathname, memoData.name);
  const showCommentPreview = !isInMemoDetailPage && computeCommentAmount(memoData) > 0;

  // The card width is only needed by the share-image dialog. Keep feed cards
@ -93,6 +110,7 @@ const MemoView: React.FC<MemoViewProps> = (props: MemoViewProps) => {
      creator,
      currentUser,
      parentPage,
+      parentScope,
      cardWidth,
      isArchived,
      readonly,
@ -107,6 +125,7 @@ const MemoView: React.FC<MemoViewProps> = (props: MemoViewProps) => {
      creator,
      currentUser,
      parentPage,
+      parentScope,
      cardWidth,
      isArchived,
      readonly,
@ -124,7 +143,7 @@ const MemoView: React.FC<MemoViewProps> = (props: MemoViewProps) => {
      ref={cardRef}
      tabIndex={readonly ? -1 : 0}
    >
-      <MemoHeader showCreator={showCreator} showVisibility={showVisibility} showPinned={showPinned} />
+      <MemoHeader showCreator={showCreator} showVisibility={showVisibility} showPinned={showPinned} showSpace={showSpace} />

      <MemoBody compact={compact} />

--- a/web/src/components/MemoView/MemoViewContext.tsx
+++ b/web/src/components/MemoView/MemoViewContext.tsx
@ -7,12 +7,14 @@ import { MemoRelation_Type } from "@/types/proto/api/v1/memo_service_pb";
 import type { User } from "@/types/proto/api/v1/user_service_pb";
 import type { PreviewMediaItem } from "@/utils/media-item";
 import { RELATIVE_TIME_THRESHOLD_MS } from "./constants";
+import { isMemoDetailPath, type MemoOriginScope } from "./navigation";

 export interface MemoViewContextValue {
  memo: Memo;
  creator: User | undefined;
  currentUser: User | undefined;
  parentPage: string;
+  parentScope: MemoOriginScope;
  cardWidth: number;
  isArchived: boolean;
  readonly: boolean;
@ -41,7 +43,7 @@ export const useMemoViewDerived = () => {
  const { timeBasis } = useView();
  const location = useLocation();

-  const isInMemoDetailPage = location.pathname.startsWith(`/${memo.name}`) || location.pathname.startsWith("/memos/shares/");
+  const isInMemoDetailPage = isMemoDetailPath(location.pathname, memo.name);
  const commentAmount = computeCommentAmount(memo);

  const createTime = memo.createTime ? timestampDate(memo.createTime) : undefined;
--- a/web/src/components/MemoView/components/MemoBody.tsx
+++ b/web/src/components/MemoView/components/MemoBody.tsx
@ -32,7 +32,8 @@ const BlurOverlay: React.FC<{ onClick?: () => void }> = ({ onClick }) => {
 };

 const MemoBody: React.FC<MemoBodyProps> = ({ compact }) => {
-  const { memo, parentPage, showBlurredContent, blurred, readonly, openEditor, openPreview, toggleBlurVisibility } = useMemoViewContext();
+  const { memo, parentPage, parentScope, showBlurredContent, blurred, readonly, openEditor, openPreview, toggleBlurVisibility } =
+    useMemoViewContext();

  const { handleMemoContentClick, handleMemoContentDoubleClick } = useMemoHandlers({ readonly, openEditor, openPreview });

@ -56,6 +57,8 @@ const MemoBody: React.FC<MemoBodyProps> = ({ compact }) => {
        <ClampedSection enabled={Boolean(compact)}>
          <MemoContent
            memoName={memo.name}
+            parentPage={parentPage}
+            parentScope={parentScope}
            content={memo.content}
            attachments={memo.attachments}
            onClick={handleMemoContentClick}
@ -63,7 +66,7 @@ const MemoBody: React.FC<MemoBodyProps> = ({ compact }) => {
            compact={Boolean(compact)}
          />
          <AttachmentListView attachments={attachmentOnlyItems} onImagePreview={openPreview} />
-          <RelationListView relations={referencedMemos} currentMemoName={memo.name} parentPage={parentPage} />
+          <RelationListView relations={referencedMemos} currentMemoName={memo.name} parentPage={parentPage} parentScope={parentScope} />
          {memo.location && <LocationDisplayView location={memo.location} />}
        </ClampedSection>
        <MemoReactionListView memo={memo} reactions={memo.reactions} />
--- a/web/src/components/MemoView/components/MemoCommentListView.tsx
+++ b/web/src/components/MemoView/components/MemoCommentListView.tsx
@ -6,9 +6,10 @@ import { useNearViewport } from "@/hooks/useNearViewport";
 import { useUsersByNames } from "@/hooks/useUserQueries";
 import { extractMemoIdFromName } from "@/lib/resource-names";
 import { useMemoViewContext, useMemoViewDerived } from "../MemoViewContext";
+import { createMemoNavigationState } from "../navigation";

 const MemoCommentListView: React.FC = () => {
-  const { memo } = useMemoViewContext();
+  const { memo, parentPage, parentScope } = useMemoViewContext();
  const { isInMemoDetailPage, commentAmount } = useMemoViewDerived();
  const { ref: viewportRef, isNearViewport } = useNearViewport<HTMLDivElement>();

@ -30,6 +31,7 @@ const MemoCommentListView: React.FC = () => {
        <span className="text-xs text-muted-foreground">Comments{commentAmount > 1 ? ` (${commentAmount})` : ""}</span>
        <Link
          to={`/${memo.name}#comments`}
+          state={createMemoNavigationState(parentPage, parentScope)}
          className="flex items-center gap-0.5 text-xs text-muted-foreground/80 hover:underline underline-offset-2 transition-colors"
        >
          View all
@ -43,6 +45,7 @@ const MemoCommentListView: React.FC = () => {
          <Link
            key={comment.name}
            to={`/${memo.name}#${uid}`}
+            state={createMemoNavigationState(parentPage, parentScope)}
            viewTransition
            className="rounded-md bg-muted/40 px-2 py-1 transition-colors hover:bg-muted/60"
          >
--- a/web/src/components/MemoView/components/MemoHeader.tsx
+++ b/web/src/components/MemoView/components/MemoHeader.tsx
@ -17,21 +17,23 @@ import UserAvatar from "../../UserAvatar";
 import VisibilityIcon from "../../VisibilityIcon";
 import { useMemoActions } from "../hooks";
 import { useMemoViewContext, useMemoViewDerived } from "../MemoViewContext";
+import { createMemoNavigationState } from "../navigation";
 import type { MemoHeaderProps } from "../types";
+import MemoSpaceBadge from "./MemoSpaceBadge";

-const MemoHeader: React.FC<MemoHeaderProps> = ({ showCreator, showVisibility, showPinned }) => {
+const MemoHeader: React.FC<MemoHeaderProps> = ({ showCreator, showVisibility, showPinned, showSpace }) => {
  const t = useTranslate();
  const [reactionSelectorOpen, setReactionSelectorOpen] = useState(false);

-  const { memo, creator, currentUser, parentPage, isArchived, readonly, openEditor } = useMemoViewContext();
+  const { memo, creator, currentUser, parentPage, parentScope, isArchived, readonly, openEditor } = useMemoViewContext();
  const { createTime, updateTime, displayTime: memoDisplayTime, isDisplayingUpdatedTime, relativeTimeFormat } = useMemoViewDerived();
  const { newMemoName } = useNewMemo();
  const visibilityOption = getVisibilityOption(memo.visibility);

  const navigateTo = useNavigateTo();
  const handleGotoMemoDetailPage = useCallback(() => {
-    navigateTo(`/${memo.name}`, { state: { from: parentPage } });
-  }, [memo.name, parentPage, navigateTo]);
+    navigateTo(`/${memo.name}`, { state: createMemoNavigationState(parentPage, parentScope) });
+  }, [memo.name, parentPage, parentScope, navigateTo]);

  const { unpinMemo } = useMemoActions(memo);

@ -54,14 +56,24 @@ const MemoHeader: React.FC<MemoHeaderProps> = ({ showCreator, showVisibility, sh
        ? `${t("common.last-updated-at")}: ${updateTime.toLocaleString(i18n.language)}`
        : undefined,
  };
+  const spaceMetadata = showSpace && memo.space ? <MemoSpaceBadge spaceName={memo.space} /> : null;

  return (
-    <div className="w-full flex flex-row justify-between items-center gap-2">
-      <div className="w-auto max-w-[calc(100%-8rem)] grow flex flex-row justify-start items-center">
+    <div className="flex w-full items-center justify-between gap-2">
+      <div className="flex min-w-0 flex-1 items-center gap-2">
        {showCreator && creator ? (
-          <CreatorDisplay creator={creator} displayTime={displayTime} timeTooltip={timeTooltip} onGotoDetail={handleGotoMemoDetailPage} />
+          <CreatorDisplay
+            creator={creator}
+            displayTime={displayTime}
+            timeTooltip={timeTooltip}
+            trailingMetadata={spaceMetadata}
+            onGotoDetail={handleGotoMemoDetailPage}
+          />
        ) : (
-          <TimeDisplay displayTime={displayTime} timeTooltip={timeTooltip} onGotoDetail={handleGotoMemoDetailPage} />
+          <div data-slot="memo-header-meta" className="flex min-w-0 items-center gap-1.5">
+            <TimeDisplay displayTime={displayTime} timeTooltip={timeTooltip} onGotoDetail={handleGotoMemoDetailPage} />
+            {spaceMetadata}
+          </div>
        )}
        {memo.name === newMemoName && (
          <span className="ml-2 shrink-0 rounded-full bg-primary/10 px-1.5 py-0.5 text-xs font-medium leading-none text-primary">
@ -103,7 +115,7 @@ const MemoHeader: React.FC<MemoHeaderProps> = ({ showCreator, showVisibility, sh
          </TooltipProvider>
        )}

-        <MemoActionMenu memo={memo} readonly={readonly} onEdit={openEditor} />
+        <MemoActionMenu memo={memo} parentScope={parentScope} readonly={readonly} onEdit={openEditor} />
      </div>
    </div>
  );
@ -113,15 +125,16 @@ interface CreatorDisplayProps {
  creator: User;
  displayTime: React.ReactNode;
  timeTooltip: TimeTooltipContent;
+  trailingMetadata?: React.ReactNode;
  onGotoDetail: () => void;
 }

-const CreatorDisplay: React.FC<CreatorDisplayProps> = ({ creator, displayTime, timeTooltip, onGotoDetail }) => (
-  <div className="w-full flex flex-row justify-start items-center">
+const CreatorDisplay: React.FC<CreatorDisplayProps> = ({ creator, displayTime, timeTooltip, trailingMetadata, onGotoDetail }) => (
+  <div className="flex min-w-0 items-center">
    <Link className="w-auto hover:opacity-80 rounded-md transition-colors" to={`/u/${encodeURIComponent(creator.username)}`} viewTransition>
      <UserAvatar className="mr-2 shrink-0" avatarUrl={creator.avatarUrl} />
    </Link>
-    <div className="w-full flex flex-col justify-center items-start">
+    <div className="flex min-w-0 flex-col items-start justify-center">
      <Link
        className="block leading-tight hover:opacity-80 rounded-md transition-colors truncate text-muted-foreground"
        to={`/u/${encodeURIComponent(creator.username)}`}
@ -129,14 +142,18 @@ const CreatorDisplay: React.FC<CreatorDisplayProps> = ({ creator, displayTime, t
      >
        {creator.displayName || creator.username}
      </Link>
-      <TimeTooltip content={timeTooltip}>
-        <span
-          className="w-auto -mt-0.5 text-xs leading-tight text-muted-foreground select-none cursor-pointer hover:opacity-80 transition-colors text-left"
-          onClick={onGotoDetail}
-        >
-          {displayTime}
-        </span>
-      </TimeTooltip>
+      <div data-slot="memo-header-meta" className="flex min-w-0 items-center gap-1.5">
+        <TimeTooltip content={timeTooltip}>
+          <button
+            type="button"
+            className="w-auto -mt-0.5 border-0 bg-transparent p-0 text-xs leading-tight text-muted-foreground select-none cursor-pointer hover:opacity-80 transition-colors text-left"
+            onClick={onGotoDetail}
+          >
+            {displayTime}
+          </button>
+        </TimeTooltip>
+        {trailingMetadata}
+      </div>
    </div>
  </div>
 );
@ -164,12 +181,13 @@ interface TimeDisplayProps {

 const TimeDisplay: React.FC<TimeDisplayProps> = ({ displayTime, timeTooltip, onGotoDetail }) => (
  <TimeTooltip content={timeTooltip}>
-    <span
-      className="w-auto text-sm leading-tight text-muted-foreground select-none cursor-pointer hover:text-foreground transition-colors text-left"
+    <button
+      type="button"
+      className="w-auto border-0 bg-transparent p-0 text-sm leading-tight text-muted-foreground select-none cursor-pointer hover:text-foreground transition-colors text-left"
      onClick={onGotoDetail}
    >
      {displayTime}
-    </span>
+    </button>
  </TimeTooltip>
 );

--- a/web/src/components/MemoView/components/MemoSpaceBadge.tsx
+++ b/web/src/components/MemoView/components/MemoSpaceBadge.tsx
@ -0,0 +1,37 @@
+import { UserLockIcon } from "lucide-react";
+import { Badge } from "@/components/ui/badge";
+import { useSpaceContext } from "@/contexts/SpaceContext";
+import { useTranslate } from "@/utils/i18n";
+
+interface MemoSpaceBadgeProps {
+  spaceName?: string;
+}
+
+const MemoSpaceBadge = ({ spaceName }: MemoSpaceBadgeProps) => {
+  const t = useTranslate();
+  const { spaces } = useSpaceContext();
+
+  if (!spaceName) return null;
+
+  const spaceLabel = t("space.current");
+  const knownTitle = spaces.find((space) => space.name === spaceName)?.title.trim();
+  const title = knownTitle || spaceLabel;
+  const accessibleLabel = knownTitle ? `${spaceLabel}: ${knownTitle}` : spaceLabel;
+
+  return (
+    <Badge
+      variant="outline"
+      shape="pill"
+      title={accessibleLabel}
+      className="min-w-0 max-w-24 shrink gap-1 border-border/60 bg-muted/30 px-1.5 py-0 text-[11px] font-normal text-muted-foreground sm:max-w-32"
+    >
+      <UserLockIcon aria-hidden="true" className="size-3 shrink-0" strokeWidth={1.8} />
+      <span className="truncate">
+        {knownTitle && <span className="sr-only">{spaceLabel}: </span>}
+        {title}
+      </span>
+    </Badge>
+  );
+};
+
+export default MemoSpaceBadge;
--- a/web/src/components/MemoView/navigation.ts
+++ b/web/src/components/MemoView/navigation.ts
@ -0,0 +1,119 @@
+import { isMemoScopeRoute } from "@/lib/memo-views";
+import { ROUTES } from "@/router/routes";
+
+export type MemoOriginScope = "all" | "preserve";
+
+export interface MemoNavigationState {
+  from: string;
+  fromScope: MemoOriginScope;
+}
+
+interface ResolveMemoDetailOriginOptions {
+  memoArchived?: boolean;
+}
+
+interface ResolveMemoParentPageOptions {
+  explicitParentPage?: string;
+  explicitParentScope?: MemoOriginScope;
+  pathname: string;
+  search: string;
+  memoName: string;
+}
+
+const normalizePathname = (pathname: string): string => {
+  const normalized = pathname.length > 1 ? pathname.replace(/\/+$/, "") : pathname;
+  return normalized.toLowerCase();
+};
+
+/** Whether the current route is any canonical or shared Memo detail page. */
+export const isMemoResourcePath = (pathname: string): boolean => {
+  const normalizedPath = normalizePathname(pathname);
+  const sharedMemoPrefix = `${ROUTES.SHARED_MEMO}/`;
+  if (normalizedPath.startsWith(sharedMemoPrefix)) {
+    const shareToken = normalizedPath.slice(sharedMemoPrefix.length);
+    return shareToken.length > 0 && !shareToken.includes("/");
+  }
+
+  const directMemoPrefix = "/memos/";
+  if (!normalizedPath.startsWith(directMemoPrefix)) return false;
+  const memoID = normalizedPath.slice(directMemoPrefix.length);
+  return memoID.length > 0 && !memoID.includes("/");
+};
+
+/** Whether a page consumes the remembered All / exact-Space collection scope. */
+export const isMemoCollectionOrigin = (page: string): boolean => {
+  const pathname = page.split(/[?#]/, 1)[0] || ROUTES.HOME;
+  return isMemoScopeRoute(pathname) || normalizePathname(pathname) === ROUTES.ATTACHMENTS;
+};
+
+export const createMemoNavigationState = (from: string, fromScope: MemoOriginScope): MemoNavigationState => ({ from, fromScope });
+
+/** Reads router state while remaining compatible with older `{ from }` links. */
+export const resolveMemoDetailOrigin = (
+  state: unknown,
+  options: ResolveMemoDetailOriginOptions = {},
+): { parentPage: string; parentScope: MemoOriginScope } => {
+  const value = state && typeof state === "object" ? (state as { from?: unknown; fromScope?: unknown }) : undefined;
+  const explicitParentPage = typeof value?.from === "string" ? value.from : undefined;
+  const hasExplicitParent = explicitParentPage !== undefined;
+  const parentPage = explicitParentPage || (options.memoArchived ? ROUTES.ARCHIVED : ROUTES.HOME);
+  const parentScope =
+    value?.fromScope === "all" || value?.fromScope === "preserve"
+      ? value.fromScope
+      : hasExplicitParent && isMemoCollectionOrigin(parentPage)
+        ? "preserve"
+        : "all";
+  return { parentPage, parentScope };
+};
+
+/** Whether the current route is the canonical detail page for this memo. */
+export const isMemoDetailPath = (pathname: string, memoName: string): boolean => {
+  const normalizedPath = normalizePathname(pathname);
+  if (normalizedPath === `/${memoName}`.toLowerCase()) return true;
+  return normalizedPath.startsWith(`${ROUTES.SHARED_MEMO}/`) && isMemoResourcePath(normalizedPath);
+};
+
+/**
+ * Captures the list page that opened a memo so canonical detail routes can
+ * return to the real collection lens instead of assuming Home.
+ */
+export const resolveMemoOrigin = ({
+  explicitParentPage,
+  explicitParentScope,
+  pathname,
+  search,
+  memoName,
+}: ResolveMemoParentPageOptions): { parentPage: string; parentScope: MemoOriginScope } => {
+  if (explicitParentPage !== undefined) {
+    const parentPage = explicitParentPage || ROUTES.HOME;
+    return {
+      parentPage,
+      parentScope: explicitParentScope ?? (isMemoCollectionOrigin(parentPage) ? "preserve" : "all"),
+    };
+  }
+
+  if (isMemoDetailPath(pathname, memoName)) {
+    return { parentPage: ROUTES.HOME, parentScope: "all" };
+  }
+
+  return {
+    parentPage: `${pathname}${search}`,
+    parentScope: isMemoCollectionOrigin(pathname) ? "preserve" : "all",
+  };
+};
+
+export const resolveMemoParentPage = (options: ResolveMemoParentPageOptions): string => resolveMemoOrigin(options).parentPage;
+
+/** Replaces only the memo filter while preserving the rest of the origin query. */
+export const withMemoFilter = (page: string, filter: string): string => {
+  const [pathAndSearch] = page.split("#", 1);
+  const questionMark = pathAndSearch.indexOf("?");
+  const pathname = questionMark === -1 ? pathAndSearch : pathAndSearch.slice(0, questionMark);
+  const search = questionMark === -1 ? "" : pathAndSearch.slice(questionMark + 1);
+  const searchParams = new URLSearchParams(search);
+  if (/^\/u\//i.test(pathname) && searchParams.get("view") === "map") {
+    searchParams.delete("view");
+  }
+  searchParams.set("filter", filter);
+  return `${pathname || ROUTES.HOME}?${searchParams.toString()}`;
+};
--- a/web/src/components/MemoView/types.ts
+++ b/web/src/components/MemoView/types.ts
@ -1,4 +1,5 @@
 import type { Memo } from "@/types/proto/api/v1/memo_service_pb";
+import type { MemoOriginScope } from "./navigation";

 export interface MemoViewProps {
  memo: Memo;
@ -6,8 +7,10 @@ export interface MemoViewProps {
  showCreator?: boolean;
  showVisibility?: boolean;
  showPinned?: boolean;
+  showSpace?: boolean;
  className?: string;
  parentPage?: string;
+  parentScope?: MemoOriginScope;
  shareImageDialogOpen?: boolean;
  onShareImageDialogOpenChange?: (open: boolean) => void;
 }
@ -16,6 +19,7 @@ export interface MemoHeaderProps {
  showCreator?: boolean;
  showVisibility?: boolean;
  showPinned?: boolean;
+  showSpace?: boolean;
 }

 export interface MemoBodyProps {
--- a/web/src/components/UserMemoMap/UserMemoMap.tsx
+++ b/web/src/components/UserMemoMap/UserMemoMap.tsx
@ -6,7 +6,9 @@ import { ArrowUpRightIcon, MapPinIcon } from "lucide-react";
 import { useEffect, useMemo } from "react";
 import { MapContainer, Marker, Popup, useMap } from "react-leaflet";
 import MarkerClusterGroup from "react-leaflet-cluster";
-import { Link } from "react-router-dom";
+import { Link, useLocation } from "react-router-dom";
+import MemoSpaceBadge from "@/components/MemoView/components/MemoSpaceBadge";
+import { createMemoNavigationState } from "@/components/MemoView/navigation";
 import { defaultMarkerIcon, ThemedTileLayer } from "@/components/map/map-utils";
 import { useInfiniteMemos } from "@/hooks/useMemoQueries";
 import { buildMemoCreatorFilter } from "@/lib/resource-names";
@ -48,6 +50,8 @@ const MapFitBounds = ({ memos }: { memos: Memo[] }) => {
 };

 const UserMemoMap = ({ creator, className }: Props) => {
+  const location = useLocation();
+  const parentPage = `${location.pathname}${location.search}`;
  const creatorFilter = useMemo(() => buildMemoCreatorFilter(creator), [creator]);

  const { data, isLoading } = useInfiniteMemos(
@ -130,9 +134,12 @@ const UserMemoMap = ({ creator, className }: Props) => {
                <div className="flex flex-col gap-2.5 p-3">
                  <div className="flex items-start justify-between gap-3">
                    <div className="space-y-1">
-                      <span className="inline-flex rounded-full border border-border/70 bg-muted/50 px-2 py-0.5 text-[10px] font-medium uppercase tracking-[0.14em] text-muted-foreground">
-                        Memo
-                      </span>
+                      <div className="flex flex-wrap items-center gap-1">
+                        <span className="inline-flex rounded-full border border-border/70 bg-muted/50 px-2 py-0.5 text-[10px] font-medium uppercase tracking-[0.14em] text-muted-foreground">
+                          Memo
+                        </span>
+                        <MemoSpaceBadge spaceName={memo.space} />
+                      </div>
                      <span className="block text-[11px] font-medium text-muted-foreground">
                        {memo.createTime &&
                          timestampDate(memo.createTime).toLocaleDateString(undefined, {
@ -144,6 +151,7 @@ const UserMemoMap = ({ creator, className }: Props) => {
                    </div>
                    <Link
                      to={`/memos/${memo.name.split("/").pop()}`}
+                      state={createMemoNavigationState(parentPage, "all")}
                      className="inline-flex items-center gap-1 rounded-full border border-border bg-background px-2.5 py-1 text-[11px] font-medium text-foreground transition-all hover:border-primary/40 hover:text-primary"
                    >
                      Open
--- a/web/src/contexts/AppSidebarContext.tsx
+++ b/web/src/contexts/AppSidebarContext.tsx
@ -1,5 +1,6 @@
 import { createContext, type ReactNode, useCallback, useContext, useEffect, useMemo, useState } from "react";
 import { useLocation } from "react-router-dom";
+import type { MemoOriginScope } from "@/components/MemoView/navigation";
 import type { MemoScope } from "@/lib/memo-views";
 import type { Memo } from "@/types/proto/api/v1/memo_service_pb";

@ -9,6 +10,7 @@ export type InboxFilter = "all" | "unread" | "archived";
 export interface MemoDetailSidebarDescriptor {
  memo: Memo;
  from?: string;
+  fromScope?: MemoOriginScope;
  readonly?: boolean;
  onShareImageOpen?: () => void;
 }
--- a/web/src/contexts/GlobalMemoEditorContext.tsx
+++ b/web/src/contexts/GlobalMemoEditorContext.tsx
@ -1,5 +1,7 @@
 import { Dialog as DialogPrimitive } from "@base-ui/react/dialog";
 import { type ComponentType, createContext, type ReactNode, useCallback, useContext, useEffect, useMemo, useRef, useState } from "react";
+import { useLocation } from "react-router-dom";
+import { getRouteActionPolicy } from "@/components/AppSidebar/routes";
 import { loadMemoEditor } from "@/components/MemoEditor/loader";
 import type { MemoEditorProps } from "@/components/MemoEditor/types";
 import { VisuallyHidden } from "@/components/ui/visually-hidden";
@ -36,10 +38,13 @@ const findVisibleFocusTarget = (selector: string): HTMLElement | null =>

 export function GlobalMemoEditorProvider({ children }: { children: ReactNode }) {
  const t = useTranslate();
+  const location = useLocation();
  const currentUserName = useCurrentUser()?.name;
  const { selectedSpaceName } = useSpaceContext();
  const { isUserSettingsInitialized } = useAuth();
  const { setMobileOpen, setQuickFindOpen } = useAppSidebar();
+  const routePolicy = getRouteActionPolicy(location.pathname);
+  const composeSpace = routePolicy.composePlacement === "remembered-space" ? selectedSpaceName : undefined;
  // One snapshot taken when the composer opens: keyed by the user who opened it, so
  // signing out closes the composer in the same render and a different user signing
  // in cannot resurrect it, and pinned to the Space that was selected at that moment.
@ -83,10 +88,10 @@ export function GlobalMemoEditorProvider({ children }: { children: ReactNode })
      .then(({ default: MemoEditor }) => {
        if (openRequestVersionRef.current !== requestVersion) return;
        setEditorComponent(() => MemoEditor);
-        setOpened({ user: currentUserName, space: selectedSpaceName });
+        setOpened({ user: currentUserName, space: composeSpace });
      })
      .catch(() => undefined);
-  }, [canOpen, currentUserName, selectedSpaceName, setMobileOpen, setQuickFindOpen]);
+  }, [canOpen, composeSpace, currentUserName, setMobileOpen, setQuickFindOpen]);

  useEffect(() => {
    // RootLayout remains mounted when a public instance moves from Home to
--- a/web/src/contexts/SpaceContext.tsx
+++ b/web/src/contexts/SpaceContext.tsx
@ -1,12 +1,14 @@
 import { createContext, type ReactNode, useCallback, useContext, useEffect, useMemo, useRef, useState } from "react";
-import { useNavigate } from "react-router-dom";
+import { useLocation, useNavigate } from "react-router-dom";
+import { routeSupportsCollectionScope } from "@/components/AppSidebar/routes";
 import useCurrentUser from "@/hooks/useCurrentUser";
 import { useSpaces } from "@/hooks/useSpaceQueries";
-import { buildSpaceFilter } from "@/lib/cel-filter";
+import { buildCollectionScopeFilter, type CollectionScope } from "@/lib/cel-filter";
 import { ROUTES } from "@/router/routes";
 import type { Space } from "@/types/proto/api/v1/space_service_pb";

 const SELECTED_SPACE_STORAGE_PREFIX = "memos-selected-space:";
+const ALL_COLLECTION_SCOPE: CollectionScope = { kind: "all" };

 export const getSelectedSpaceStorageKey = (userName: string) => `${SELECTED_SPACE_STORAGE_PREFIX}${userName}`;

@ -35,9 +37,12 @@ interface SpaceContextValue {
  spaces: Space[];
  selectedSpace?: Space;
  selectedSpaceName?: string;
+  collectionScope: CollectionScope;
  memoFilter?: string;
  isLoadingSpaces: boolean;
  isSpacesError: boolean;
+  /** Selects All without changing the current route. */
+  clearSelectedSpace: () => void;
  selectSpace: (space: Space) => void;
  selectMemos: () => void;
 }
@ -49,12 +54,13 @@ const SpaceContext = createContext<SpaceContextValue | null>(null);
 const NO_SPACES: Space[] = [];

 function UserSpaceSession({ userName, children }: { userName: string; children: ReactNode }) {
-  // Switching context lands on that context's feed, so the switcher doubles as the
-  // brand slot's way home. Held in a ref because `navigate` changes identity on every
-  // route change, which would otherwise rebuild the context value — and re-render the
-  // global composer and the editor tree it hosts — on each navigation.
+  // Keep router values in refs so switching scope does not make the context callbacks
+  // change identity whenever the user navigates.
+  const location = useLocation();
  const navigate = useNavigate();
+  const pathnameRef = useRef(location.pathname);
  const navigateRef = useRef(navigate);
+  pathnameRef.current = location.pathname;
  navigateRef.current = navigate;

  const [selectedSpaceName, setSelectedSpaceName] = useState(() => readSelectedSpaceName(userName));
@ -63,6 +69,10 @@ function UserSpaceSession({ userName, children }: { userName: string; children:
  const spaces = spacesQuery.data ?? NO_SPACES;
  const listedSelectedSpace = spaces.find((space) => space.name === selectedSpaceName);
  const selectedSpace = listedSelectedSpace ?? (optimisticSpace?.name === selectedSpaceName ? optimisticSpace : undefined);
+  const collectionScope = useMemo<CollectionScope>(
+    () => (selectedSpaceName ? { kind: "space", name: selectedSpaceName } : ALL_COLLECTION_SCOPE),
+    [selectedSpaceName],
+  );

  useEffect(() => {
    if (listedSelectedSpace && optimisticSpace?.name === listedSelectedSpace.name) {
@ -79,35 +89,59 @@ function UserSpaceSession({ userName, children }: { userName: string; children:
    setSelectedSpaceName(undefined);
  }, [selectedSpace, selectedSpaceName, spacesQuery.isSuccess, userName]);

+  const navigateAfterScopeChange = useCallback(() => {
+    // Scope and collection lens are independent. Preserve the active lens when
+    // switching All/Space; global and resource routes fall back to My memos.
+    if (!routeSupportsCollectionScope(pathnameRef.current)) {
+      navigateRef.current(ROUTES.HOME);
+    }
+  }, []);
+
  const selectSpace = useCallback(
    (space: Space) => {
      writeSelectedSpaceName(userName, space.name);
      setOptimisticSpace(space);
      setSelectedSpaceName(space.name);
-      navigateRef.current(ROUTES.HOME);
+      navigateAfterScopeChange();
    },
-    [userName],
+    [navigateAfterScopeChange, userName],
  );

-  const selectMemos = useCallback(() => {
+  const clearSelectedSpace = useCallback(() => {
    writeSelectedSpaceName(userName, undefined);
    setOptimisticSpace(undefined);
    setSelectedSpaceName(undefined);
-    navigateRef.current(ROUTES.HOME);
  }, [userName]);

+  const selectMemos = useCallback(() => {
+    clearSelectedSpace();
+    navigateAfterScopeChange();
+  }, [clearSelectedSpace, navigateAfterScopeChange]);
+
  const value = useMemo<SpaceContextValue>(
    () => ({
      spaces,
      selectedSpace,
      selectedSpaceName,
-      memoFilter: buildSpaceFilter(selectedSpaceName),
+      collectionScope,
+      memoFilter: buildCollectionScopeFilter(collectionScope),
      isLoadingSpaces: spacesQuery.isPending,
      isSpacesError: spacesQuery.isError,
+      clearSelectedSpace,
      selectSpace,
      selectMemos,
    }),
-    [selectMemos, selectSpace, selectedSpace, selectedSpaceName, spaces, spacesQuery.isError, spacesQuery.isPending],
+    [
+      clearSelectedSpace,
+      collectionScope,
+      selectMemos,
+      selectSpace,
+      selectedSpace,
+      selectedSpaceName,
+      spaces,
+      spacesQuery.isError,
+      spacesQuery.isPending,
+    ],
  );

  return <SpaceContext.Provider value={value}>{children}</SpaceContext.Provider>;
@ -115,8 +149,10 @@ function UserSpaceSession({ userName, children }: { userName: string; children:

 const anonymousValue: SpaceContextValue = {
  spaces: [],
+  collectionScope: ALL_COLLECTION_SCOPE,
  isLoadingSpaces: false,
  isSpacesError: false,
+  clearSelectedSpace: () => undefined,
  selectSpace: () => undefined,
  selectMemos: () => undefined,
 };
--- a/web/src/hooks/useFilteredMemoStats.ts
+++ b/web/src/hooks/useFilteredMemoStats.ts
@ -24,7 +24,6 @@ export interface UseFilteredMemoStatsOptions {
  context?: MemoStatsContext;
  enabled?: boolean;
  filter?: string;
-  includeSpaceVisibility?: boolean;
 }

 const toDateString = (date: Date) => dayjs(date).format("YYYY-MM-DD");
@ -41,7 +40,7 @@ const timestampsForBasis = (stats: UserStats, basis: MemoTimeBasis) => {
 };

 export const useFilteredMemoStats = (options: UseFilteredMemoStatsOptions = {}): FilteredMemoStats => {
-  const { userName, context, enabled = true, filter, includeSpaceVisibility = false } = options;
+  const { userName, context, enabled = true, filter } = options;
  const currentUser = useCurrentUser();
  const { timeBasis } = useView();

@ -50,12 +49,7 @@ export const useFilteredMemoStats = (options: UseFilteredMemoStatsOptions = {}):
  // explore/archived: fetch backend grouped stats and aggregate them locally.
  // ListAllUserStats AND's the request filter with the server's auth filter, so
  // private memos are not included unless explicitly visible to the current user.
-  const exploreVisibilityFilter =
-    currentUser != null
-      ? includeSpaceVisibility
-        ? 'visibility in ["PUBLIC", "PROTECTED", "SPACE"]'
-        : 'visibility in ["PUBLIC", "PROTECTED"]'
-      : 'visibility in ["PUBLIC"]';
+  const exploreVisibilityFilter = currentUser != null ? 'visibility in ["PUBLIC", "PROTECTED", "SPACE"]' : 'visibility in ["PUBLIC"]';
  const allUserStatsRequest =
    context === "explore"
      ? { state: State.NORMAL, filter: combineCELFilters(filter, exploreVisibilityFilter) }
--- a/web/src/lib/cel-filter.ts
+++ b/web/src/lib/cel-filter.ts
@ -3,4 +3,7 @@ export const combineCELFilters = (...filters: Array<string | undefined>): string
  return conditions.length === 0 ? undefined : conditions.map((filter) => `(${filter})`).join(" && ");
 };

-export const buildSpaceFilter = (spaceName?: string): string => (spaceName ? `space == ${JSON.stringify(spaceName)}` : "space == null");
+export type CollectionScope = { kind: "all" } | { kind: "space"; name: string };
+
+export const buildCollectionScopeFilter = (scope: CollectionScope): string | undefined =>
+  scope.kind === "space" ? `space == ${JSON.stringify(scope.name)}` : undefined;
--- a/web/src/lib/memo-views.ts
+++ b/web/src/lib/memo-views.ts
@ -10,8 +10,15 @@ export const getMemoViewId = (name: string): string => {
  return parts.length === 4 ? parts[3] : name;
 };

-export const isMemoScopeRoute = (pathname: string): boolean =>
-  pathname === ROUTES.HOME || pathname === ROUTES.EXPLORE || pathname === ROUTES.ARCHIVED;
+const cleanPathname = (value: string): string => {
+  const pathname = value.split(/[?#]/, 1)[0] || ROUTES.HOME;
+  return pathname.length > 1 ? pathname.replace(/\/+$/, "") : pathname;
+};
+
+export const isMemoScopeRoute = (pathname: string): boolean => {
+  const comparablePath = cleanPathname(pathname).toLowerCase();
+  return comparablePath === ROUTES.HOME || comparablePath === ROUTES.EXPLORE || comparablePath === ROUTES.ARCHIVED;
+};

 export const getMemoScopePath = (scope: MemoScope): string => {
  if (scope === "explore") return ROUTES.EXPLORE;
@ -19,8 +26,6 @@ export const getMemoScopePath = (scope: MemoScope): string => {
  return ROUTES.HOME;
 };

-const cleanPathname = (value: string): string => value.split(/[?#]/, 1)[0] || ROUTES.HOME;
-
 interface ResolveMemoScopeOptions {
  currentUsername?: string;
  detailFrom?: string;
@ -30,23 +35,24 @@ interface ResolveMemoScopeOptions {

 export const resolveMemoScope = (pathname: string, options: ResolveMemoScopeOptions = {}): MemoScope => {
  const cleanPath = cleanPathname(pathname);
-  if (cleanPath === ROUTES.EXPLORE) return "explore";
-  if (cleanPath === ROUTES.ARCHIVED) return "archived";
-  if (cleanPath === ROUTES.HOME) return "home";
+  const comparablePath = cleanPath.toLowerCase();
+  if (comparablePath === ROUTES.EXPLORE) return "explore";
+  if (comparablePath === ROUTES.ARCHIVED) return "archived";
+  if (comparablePath === ROUTES.HOME) return "home";

-  const profileMatch = cleanPath.match(/^\/u\/([^/]+)$/);
+  const profileMatch = cleanPath.match(/^\/u\/([^/]+)$/i);
  if (profileMatch) {
    return options.currentUsername && decodeURIComponent(profileMatch[1]) === options.currentUsername ? "home" : "explore";
  }

-  if (cleanPath.startsWith("/memos/") && options.detailFrom) {
+  if (comparablePath.startsWith("/memos/") && options.detailFrom) {
    return resolveMemoScope(options.detailFrom, {
      currentUsername: options.currentUsername,
      fallback: options.fallback,
    });
  }

-  if (cleanPath.startsWith("/memos/") && options.memoArchived) {
+  if (comparablePath.startsWith("/memos/") && options.memoArchived) {
    return "archived";
  }

--- a/web/src/pages/Archived.tsx
+++ b/web/src/pages/Archived.tsx
@ -8,7 +8,7 @@ import { Memo } from "@/types/proto/api/v1/memo_service_pb";

 const Archived = () => {
  const user = useCurrentUser();
-  const { memoFilter: contextFilter } = useSpaceContext();
+  const { memoFilter: contextFilter, selectedSpaceName } = useSpaceContext();

  const memoFilter = useMemoFilters({
    creatorName: user?.name,
@ -24,7 +24,9 @@ const Archived = () => {

  return (
    <PagedMemoList
-      renderer={(memo: Memo, { compact }) => <MemoView key={getMemoKey(memo)} memo={memo} showVisibility compact={compact} />}
+      renderer={(memo: Memo, { compact }) => (
+        <MemoView key={getMemoKey(memo)} memo={memo} showVisibility showSpace={!selectedSpaceName} compact={compact} />
+      )}
      listSort={listSort}
      state={State.ARCHIVED}
      orderBy={orderBy}
--- a/web/src/pages/Explore.tsx
+++ b/web/src/pages/Explore.tsx
@ -11,12 +11,10 @@ const Explore = () => {
  const { memoFilter: contextFilter, selectedSpaceName } = useSpaceContext();

  // Determine visibility filter based on authentication status
-  // - Logged-in users: Can see PUBLIC and PROTECTED memos, plus SPACE memos while a Space is selected
+  // - Logged-in users: Can see every audience the backend authorizes, including SPACE memos
  // - Visitors: Can only see PUBLIC memos
  // Note: The backend is responsible for filtering stats based on visibility permissions.
-  const visibilities = currentUser
-    ? [Visibility.PUBLIC, Visibility.PROTECTED, ...(selectedSpaceName ? [Visibility.SPACE] : [])]
-    : [Visibility.PUBLIC];
+  const visibilities = currentUser ? [Visibility.PUBLIC, Visibility.PROTECTED, Visibility.SPACE] : [Visibility.PUBLIC];

  const memoFilter = useMemoFilters({
    includeMemoViews: true,
@ -32,7 +30,9 @@ const Explore = () => {

  return (
    <PagedMemoList
-      renderer={(memo: Memo, { compact }) => <MemoView key={getMemoKey(memo)} memo={memo} showCreator showVisibility compact={compact} />}
+      renderer={(memo: Memo, { compact }) => (
+        <MemoView key={getMemoKey(memo)} memo={memo} showCreator showVisibility showSpace={!selectedSpaceName} compact={compact} />
+      )}
      listSort={listSort}
      orderBy={orderBy}
      filter={memoFilter}
--- a/web/src/pages/Home.tsx
+++ b/web/src/pages/Home.tsx
@ -41,7 +41,7 @@ const Home = () => {
      <NewMemoProvider>
        <PagedMemoList
          renderer={(memo: Memo, { compact }) => (
-            <MemoView key={getMemoKey(memo)} memo={memo} showVisibility showPinned compact={compact} />
+            <MemoView key={getMemoKey(memo)} memo={memo} showVisibility showPinned showSpace={!selectedSpaceName} compact={compact} />
          )}
          listSort={listSort}
          orderBy={orderBy}
--- a/web/src/pages/MemoDetail.tsx
+++ b/web/src/pages/MemoDetail.tsx
@ -5,6 +5,7 @@ import { Link, Navigate, useLocation, useParams } from "react-router-dom";
 import MemoCommentSection from "@/components/MemoCommentSection";
 import { MentionResolutionProvider } from "@/components/MemoContent/MentionResolutionContext";
 import MemoView from "@/components/MemoView";
+import { createMemoNavigationState, type MemoOriginScope, resolveMemoDetailOrigin } from "@/components/MemoView/navigation";
 import { useAppSidebar } from "@/contexts/AppSidebarContext";
 import { useAuth } from "@/contexts/AuthContext";
 import { useInstance } from "@/contexts/InstanceContext";
@ -13,25 +14,28 @@ import { useInfiniteMemoComments, useMemo } from "@/hooks/useMemoQueries";
 import { useSharedMemo, withShareAttachmentLinks } from "@/hooks/useMemoShareQueries";
 import { memoNamePrefix } from "@/lib/resource-names";
 import type { Attachment } from "@/types/proto/api/v1/attachment_service_pb";
+import { State } from "@/types/proto/api/v1/common_pb";
 import type { Memo } from "@/types/proto/api/v1/memo_service_pb";
 import { findMemoAnchorTarget } from "@/utils/markdown-manipulation";

 const MemoSidebarRegistration = ({
  memo,
  from,
+  fromScope,
  readonly,
  onShareImageOpen,
 }: {
  memo: Memo;
-  from?: string;
+  from: string;
+  fromScope: MemoOriginScope;
  readonly: boolean;
  onShareImageOpen: () => void;
 }) => {
  const { setMemoDetail } = useAppSidebar();

  useEffect(() => {
-    setMemoDetail({ memo, from, readonly, onShareImageOpen });
-  }, [from, memo, onShareImageOpen, readonly, setMemoDetail]);
+    setMemoDetail({ memo, from, fromScope, readonly, onShareImageOpen });
+  }, [from, fromScope, memo, onShareImageOpen, readonly, setMemoDetail]);

  useEffect(() => () => setMemoDetail(undefined), [setMemoDetail]);

@ -45,7 +49,6 @@ const MemoDetail = () => {
  const params = useParams();
  const location = useLocation();
  const { state: locationState, hash } = location;
-  const parentPage = typeof locationState?.from === "string" ? locationState.from : undefined;
  const handleShareImageOpen = useCallback(() => setShareImageDialogOpen(true), []);

  // Detect share mode from the route parameter.
@ -64,6 +67,7 @@ const MemoDetail = () => {
  const memo = isShareMode ? memoFromShare : memoFromDirect;
  const error = isShareMode ? shareError : directError;
  const isLoading = isShareMode ? shareLoading : directLoading;
+  const { parentPage, parentScope } = resolveMemoDetailOrigin(locationState, { memoArchived: memo?.state === State.ARCHIVED });
  const memoName = memo?.name ?? memoNameFromParams;
  const displayMemo = useReactMemo(() => {
    if (!memo) return undefined;
@ -121,7 +125,13 @@ const MemoDetail = () => {
  return (
    <section className="@container flex min-h-full w-full flex-col items-center pb-8 pt-3 md:pt-6">
      <MentionResolutionProvider contents={mentionResolutionContents} userNames={userResolutionNames}>
-        <MemoSidebarRegistration memo={displayMemo} from={parentPage} readonly={isShareMode} onShareImageOpen={handleShareImageOpen} />
+        <MemoSidebarRegistration
+          memo={displayMemo}
+          from={parentPage}
+          fromScope={parentScope}
+          readonly={isShareMode}
+          onShareImageOpen={handleShareImageOpen}
+        />
        <div className="w-full max-w-2xl px-4 sm:px-6">
          <div className="w-full">
            {!isShareMode && parentMemo && (
@ -129,7 +139,7 @@ const MemoDetail = () => {
                <Link
                  className="px-3 py-1 border border-border rounded-lg max-w-xs w-auto text-sm flex flex-row justify-start items-center flex-nowrap text-muted-foreground hover:shadow hover:opacity-80"
                  to={`/${parentMemo.name}`}
-                  state={locationState}
+                  state={createMemoNavigationState(parentPage, parentScope)}
                  viewTransition
                >
                  <ArrowUpLeftFromCircleIcon className="w-4 h-auto shrink-0 opacity-60 mr-2" />
@ -142,10 +152,12 @@ const MemoDetail = () => {
              memo={displayMemo}
              compact={false}
              parentPage={parentPage}
+              parentScope={parentScope}
              shareImageDialogOpen={shareImageDialogOpen}
              showCreator
              showVisibility
              showPinned
+              showSpace
              onShareImageDialogOpenChange={setShareImageDialogOpen}
            />
            {!isShareMode && (
@ -153,6 +165,7 @@ const MemoDetail = () => {
                memo={displayMemo}
                comments={comments}
                parentPage={parentPage}
+                parentScope={parentScope}
                hasMoreComments={hasNextComments}
                isFetchingMoreComments={isFetchingNextComments}
                onLoadMoreComments={fetchNextComments}
--- a/web/src/pages/UserProfile.tsx
+++ b/web/src/pages/UserProfile.tsx
@ -87,7 +87,7 @@ const UserProfile = () => {
              {activeTab === "memos" ? (
                <PagedMemoList
                  renderer={(memo: Memo, { compact }) => (
-                    <MemoView key={getMemoKey(memo)} memo={memo} showVisibility showPinned compact={compact} />
+                    <MemoView key={getMemoKey(memo)} memo={memo} showVisibility showPinned showSpace compact={compact} />
                  )}
                  listSort={listSort}
                  orderBy={orderBy}
--- a/web/src/utils/memo.ts
+++ b/web/src/utils/memo.ts
@ -1,4 +1,4 @@
-import { BoxesIcon, Globe2Icon, LockIcon, type LucideIcon, UsersIcon } from "lucide-react";
+import { Globe2Icon, LockIcon, type LucideIcon, UserLockIcon, UsersIcon } from "lucide-react";
 import { Visibility } from "@/types/proto/api/v1/memo_service_pb";

 export interface VisibilityOption {
@ -35,7 +35,7 @@ export const VISIBILITY_OPTIONS: readonly VisibilityOption[] = [
    name: "SPACE",
    labelKey: "memo.visibility.space",
    descriptionKey: "memo.visibility.space-description",
-    icon: BoxesIcon,
+    icon: UserLockIcon,
    requiresSpace: true,
  },
  {
@ -60,12 +60,12 @@ export const getVisibilityOption = (visibility: Visibility): VisibilityOption |
  VISIBILITY_OPTIONS.find((option) => option.value === visibility);

 /**
- * Audiences a memo can be set to. SPACE is offered while a Space is selected, and also
- * for a memo that already uses it — so opening one outside its Space shows its real
- * audience instead of a blank control that quietly downgrades on the next pick.
+ * Audiences a memo can be set to. SPACE is offered when the memo is placed in a
+ * Space, and also when a legacy/inconsistent memo already uses it so the control
+ * can still name its current audience instead of silently downgrading it.
 */
-export const getAssignableVisibilityOptions = (options: { spaceSelected: boolean; current?: Visibility }): VisibilityOption[] =>
-  VISIBILITY_OPTIONS.filter((option) => !option.requiresSpace || options.spaceSelected || option.value === options.current);
+export const getAssignableVisibilityOptions = (options: { hasSpacePlacement: boolean; current?: Visibility }): VisibilityOption[] =>
+  VISIBILITY_OPTIONS.filter((option) => !option.requiresSpace || options.hasSpacePlacement || option.value === options.current);

 /** Audiences offered as a persistent default. A Space-scoped default has no meaning outside a Space. */
 export const DEFAULT_VISIBILITY_OPTIONS: readonly VisibilityOption[] = VISIBILITY_OPTIONS.filter((option) => !option.requiresSpace);
--- a/web/tests/app-sidebar-logo.test.tsx
+++ b/web/tests/app-sidebar-logo.test.tsx
@ -8,6 +8,7 @@ import { SIDEBAR_SECTION_ACTION_BUTTON_CLASSES, SIDEBAR_SECTION_ACTION_ICON_CLAS
 const authState = vi.hoisted(() => ({
  currentUser: { name: "users/test" } as { name: string } | undefined,
  memoViews: [] as Array<{ name: string; title: string }>,
+  notifications: [] as Array<{ status: number }>,
 }));
 const sidebarState = vi.hoisted(() => ({
  memoScope: "home" as "home" | "explore" | "archived",
@ -21,11 +22,13 @@ const spaceState = vi.hoisted(() => ({
  spaces: [] as Array<{ name: string; title: string; description: string }>,
  selectedSpace: undefined as { name: string; title: string; description: string } | undefined,
  selectedSpaceName: undefined as string | undefined,
-  memoFilter: "space == null" as string | undefined,
+  memoFilter: undefined as string | undefined,
+  clearSelectedSpace: vi.fn(),
  selectMemos: vi.fn(),
  selectSpace: vi.fn(),
 }));
 const filteredStatsHook = vi.hoisted(() => vi.fn());
+const tagsSectionHook = vi.hoisted(() => vi.fn());

 vi.mock("@/components/MemosLogo", () => ({
  default: () => <span>Memos logo</span>,
@ -48,7 +51,10 @@ vi.mock("@/components/StatisticsView", () => ({
 }));

 vi.mock("@/components/AppSidebar/TagsSection", () => ({
-  default: () => <div>Tags</div>,
+  default: (props: unknown) => {
+    tagsSectionHook(props);
+    return <div>Tags</div>;
+  },
 }));

 vi.mock("@/contexts/AppSidebarContext", () => ({
@ -121,7 +127,7 @@ vi.mock("@/hooks/useUserQueries", () => ({
    memoViews: (parent?: string) => ["users", "memoViews", parent],
  },
  useMemoViews: () => ({ data: authState.memoViews }),
-  useNotifications: () => ({ data: [] }),
+  useNotifications: () => ({ data: authState.notifications }),
  useUser: () => ({ data: undefined }),
 }));

@ -155,6 +161,7 @@ describe("App sidebar logo", () => {
  beforeEach(() => {
    authState.currentUser = { name: "users/test" };
    authState.memoViews = [];
+    authState.notifications = [];
    sidebarState.memoScope = "home";
    sidebarState.mobileOpen = false;
    globalEditorState.canOpen = true;
@ -162,10 +169,12 @@ describe("App sidebar logo", () => {
    spaceState.spaces = [];
    spaceState.selectedSpace = undefined;
    spaceState.selectedSpaceName = undefined;
-    spaceState.memoFilter = "space == null";
+    spaceState.memoFilter = undefined;
+    spaceState.clearSelectedSpace.mockClear();
    spaceState.selectMemos.mockClear();
    spaceState.selectSpace.mockClear();
    filteredStatsHook.mockClear();
+    tagsSectionHook.mockClear();
  });

  it("shows the context switcher and opens the global memo editor", () => {
@ -181,6 +190,55 @@ describe("App sidebar logo", () => {
    expect(screen.queryByText("common.calendar")).not.toBeInTheDocument();
  });

+  it.each([
+    "/",
+    "/explore",
+    "/archived",
+    "/attachments",
+    "/Explore/",
+    "/Attachments/",
+  ])("shows the selected Space only on collection route %s", (path) => {
+    const product = { name: "spaces/product", title: "Product", description: "" };
+    spaceState.spaces = [product];
+    spaceState.selectedSpace = product;
+    spaceState.selectedSpaceName = product.name;
+    spaceState.memoFilter = 'space == "spaces/product"';
+
+    render(
+      <MemoryRouter initialEntries={[path]}>
+        <AppSidebar />
+      </MemoryRouter>,
+    );
+
+    expect(screen.getByRole("button", { name: "space.switch: Product" })).toBeInTheDocument();
+  });
+
+  it.each([
+    "/inbox",
+    "/u/alice",
+    "/setting",
+    "/about",
+    "/views",
+    "/memos/123",
+    "/memos/shares/token",
+    "/404",
+  ])("uses the instance brand instead of the remembered Space on %s", (path) => {
+    const product = { name: "spaces/product", title: "Product", description: "" };
+    spaceState.spaces = [product];
+    spaceState.selectedSpace = product;
+    spaceState.selectedSpaceName = product.name;
+    spaceState.memoFilter = 'space == "spaces/product"';
+
+    render(
+      <MemoryRouter initialEntries={[path]}>
+        <AppSidebar />
+      </MemoryRouter>,
+    );
+
+    expect(screen.getByRole("link", { name: "Memos logo" })).toHaveAttribute("href", "/");
+    expect(screen.queryByRole("button", { name: /^space\.switch:/ })).not.toBeInTheDocument();
+  });
+
  it("scopes collection statistics to the selected Space", () => {
    spaceState.selectedSpaceName = "spaces/product";
    spaceState.memoFilter = 'space == "spaces/product"';
@ -191,9 +249,61 @@ describe("App sidebar logo", () => {
      </MemoryRouter>,
    );

-    expect(filteredStatsHook).toHaveBeenCalledWith(
-      expect.objectContaining({ context: "explore", filter: 'space == "spaces/product"', includeSpaceVisibility: true }),
+    expect(filteredStatsHook).toHaveBeenCalledWith(expect.objectContaining({ context: "explore", filter: 'space == "spaces/product"' }));
+  });
+
+  it("includes authorized Space memos in All Explore statistics", () => {
+    render(
+      <MemoryRouter initialEntries={["/explore"]}>
+        <AppSidebar />
+      </MemoryRouter>,
    );
+
+    expect(filteredStatsHook).toHaveBeenCalledWith(expect.objectContaining({ context: "explore", filter: undefined }));
+  });
+
+  it("keeps Profile statistics and tag UI state independent of the remembered Space", () => {
+    spaceState.selectedSpaceName = "spaces/product";
+    spaceState.memoFilter = 'space == "spaces/product"';
+
+    render(
+      <MemoryRouter initialEntries={["/u/alice"]}>
+        <AppSidebar />
+      </MemoryRouter>,
+    );
+
+    expect(filteredStatsHook).toHaveBeenCalledWith(expect.objectContaining({ context: "profile", filter: undefined }));
+    expect(tagsSectionHook).toHaveBeenCalledWith(expect.objectContaining({ scope: "profile" }));
+  });
+
+  it("keeps Inbox compact while exposing its unread state accessibly", () => {
+    authState.notifications = [{ status: 1 }, { status: 1 }, { status: 2 }];
+
+    render(
+      <MemoryRouter initialEntries={["/inbox"]}>
+        <AppSidebar />
+      </MemoryRouter>,
+    );
+
+    const inbox = screen.getByRole("link", { name: "common.inbox, 2 inbox.unread" });
+    expect(inbox).toHaveAttribute("aria-current", "page");
+    expect(inbox).not.toHaveTextContent("common.inbox");
+    expect(inbox).not.toHaveTextContent("2");
+    expect(inbox.querySelector("[data-inbox-unread-indicator]")).not.toBeNull();
+    expect(inbox.closest("footer")).not.toBeNull();
+  });
+
+  it.each([
+    ["/Attachments/", "common.attachments"],
+    ["/Inbox/", "common.inbox"],
+  ])("keeps %s active after route normalization", (path, label) => {
+    render(
+      <MemoryRouter initialEntries={[path]}>
+        <AppSidebar />
+      </MemoryRouter>,
+    );
+
+    expect(screen.getByRole("link", { name: label })).toHaveAttribute("aria-current", "page");
  });

  it("hides the instance-level unused attachment collection in a Space", () => {
@ -240,18 +350,18 @@ describe("App sidebar logo", () => {
    expect(screen.queryByRole("link", { name: "common.home" })).not.toBeInTheDocument();
  });

-  it("falls back to the library content on a route without a specific tenant", () => {
+  it("does not inherit collection content on a route without a collection", () => {
    render(
      <MemoryRouter initialEntries={["/404"]}>
        <AppSidebar />
      </MemoryRouter>,
    );

-    expect(screen.getByText("Calendar")).toBeInTheDocument();
-    expect(screen.getByRole("region", { name: "common.statistics" })).toBeInTheDocument();
-    expect(screen.queryByRole("heading", { name: "common.statistics" })).not.toBeInTheDocument();
-    expect(screen.getByText("common.views")).toBeInTheDocument();
-    expect(screen.getByText("Tags")).toBeInTheDocument();
+    expect(screen.queryByText("Calendar")).not.toBeInTheDocument();
+    expect(screen.queryByRole("region", { name: "common.statistics" })).not.toBeInTheDocument();
+    expect(screen.queryByText("common.views")).not.toBeInTheDocument();
+    expect(screen.queryByText("Tags")).not.toBeInTheDocument();
+    expect(screen.getByRole("link", { name: "Memos logo" })).toHaveAttribute("href", "/");
    expect(screen.getByRole("link", { name: "common.attachments" })).toHaveAttribute("href", "/attachments");
    expect(screen.getByRole("link", { name: "common.inbox" })).toHaveAttribute("href", "/inbox");
    expect(screen.queryByRole("link", { name: "common.home" })).not.toBeInTheDocument();
@ -275,16 +385,16 @@ describe("App sidebar logo", () => {
    expect(screen.getByRole("link", { name: "common.sign-in-to-memos" }).closest("footer")).not.toBeNull();
  });

-  it("marks About active for a guest on the About page", () => {
+  it.each(["/about", "/About/"])("marks About active for a guest on %s", (path) => {
    authState.currentUser = undefined;
    render(
-      <MemoryRouter initialEntries={["/about"]}>
+      <MemoryRouter initialEntries={[path]}>
        <AppSidebar />
      </MemoryRouter>,
    );

    expect(screen.getByRole("link", { name: "common.about" })).toHaveAttribute("aria-current", "page");
-    expect(screen.getByText("Calendar")).toBeInTheDocument();
+    expect(screen.queryByText("Calendar")).not.toBeInTheDocument();
  });

  it("uses a compact scope menu and places views below the calendar", async () => {
@ -336,7 +446,7 @@ describe("App sidebar logo", () => {
    expect(deleteItem).toHaveAttribute("data-variant", "destructive");
  });

-  it("collapses inactive global destinations and defaults the scope icon to Home", async () => {
+  it("keeps collection navigation together and places Inbox in the user footer", async () => {
    render(
      <MemoryRouter initialEntries={["/attachments"]}>
        <AppSidebar />
@ -347,7 +457,8 @@ describe("App sidebar logo", () => {
    expectCollapsedNavPill(scopeTrigger, "common.home");

    const inbox = screen.getByRole("link", { name: "common.inbox" });
-    expectCollapsedNavPill(inbox, "common.inbox");
+    expect(inbox.closest("footer")).not.toBeNull();
+    expect(inbox.closest('nav[aria-label="Primary"]')).toBeNull();

    const attachments = screen.getByRole("link", { name: "common.attachments" });
    expectActiveNavPill(attachments, "common.attachments");
@ -399,7 +510,8 @@ describe("App sidebar logo", () => {
    );

    expect(screen.getByRole("button", { name: "Open navigation" })).toHaveAttribute("data-mobile-navigation-trigger");
-    expect(screen.getByRole("button", { name: "space.switch: common.memos" })).toHaveTextContent("Memos logo");
+    expect(screen.getByRole("link", { name: "Memos logo" })).toHaveAttribute("href", "/");
+    expect(screen.queryByRole("button", { name: /^space\.switch:/ })).not.toBeInTheDocument();
    expect(screen.queryByRole("button", { name: "common.search" })).not.toBeInTheDocument();
    expect(screen.queryByRole("button", { name: "editor.new-memo" })).not.toBeInTheDocument();
  });
--- a/web/tests/app-sidebar-routes.test.ts
+++ b/web/tests/app-sidebar-routes.test.ts
@ -1,21 +1,106 @@
 import { describe, expect, it } from "vitest";
-import { getSidebarRouteKind } from "@/components/AppSidebar/routes";
+import { getRouteActionPolicy, getSidebarRouteKind, routeSupportsCollectionScope } from "@/components/AppSidebar/routes";

 describe("sidebar route content", () => {
  it.each([
    ["/", "home"],
    ["/archived", "archived"],
    ["/explore", "explore"],
+    ["/Explore/", "explore"],
+    ["/ARCHIVED/", "archived"],
    ["/u/steven", "profile"],
+    ["/U/Steven/", "profile"],
    ["/views", "views"],
+    ["/Views/", "views"],
    ["/attachments", "attachments"],
+    ["/Attachments/", "attachments"],
    ["/inbox", "inbox"],
+    ["/Inbox/", "inbox"],
    ["/setting", "settings"],
+    ["/Setting/", "settings"],
    ["/memos/abc", "memo"],
+    ["/Memos/ABC/", "memo"],
    ["/memos/shares/token", "memo"],
+    ["/Memos/Shares/token/", "memo"],
    ["/about", "empty"],
    ["/404", "empty"],
  ])("maps %s to %s content", (path, kind) => {
    expect(getSidebarRouteKind(path)).toBe(kind);
  });
+
+  it.each([
+    ["/", true],
+    ["/explore", true],
+    ["/archived", true],
+    ["/attachments", true],
+    ["/Explore/", true],
+    ["/ARCHIVED/", true],
+    ["/Attachments/", true],
+    ["/u/steven", false],
+    ["/inbox", false],
+    ["/setting", false],
+    ["/views", false],
+    ["/about", false],
+    ["/memos/abc", false],
+    ["/memos/shares/token", false],
+    ["/404", false],
+  ])("reports whether %s supports the remembered collection scope", (path, expected) => {
+    expect(routeSupportsCollectionScope(path)).toBe(expected);
+  });
+
+  it.each(["/", "/explore", "/archived"])("keeps search and Compose in the remembered collection on %s", (path) => {
+    expect(getRouteActionPolicy(path)).toEqual({
+      searchScope: "remembered-collection",
+      composePlacement: "remembered-space",
+    });
+  });
+
+  it("keeps the remembered scope when Attachments sends search to Home", () => {
+    expect(getRouteActionPolicy("/attachments")).toEqual({
+      searchScope: "remembered-collection",
+      searchDestination: "/",
+      composePlacement: "remembered-space",
+    });
+  });
+
+  it("keeps Profile search on Profile but makes Compose unassigned", () => {
+    expect(getRouteActionPolicy("/u/steven")).toEqual({
+      searchScope: "profile",
+      searchDestination: "/u/steven",
+      composePlacement: "unassigned",
+    });
+  });
+
+  it("normalizes a Profile route without changing its spelling", () => {
+    expect(getRouteActionPolicy("/U/Steven/")).toEqual({
+      searchScope: "profile",
+      searchDestination: "/U/Steven",
+      composePlacement: "unassigned",
+    });
+  });
+
+  it.each(["/Explore/", "/ARCHIVED/"])("keeps normalized collection route %s in the remembered scope", (path) => {
+    expect(getRouteActionPolicy(path)).toEqual({
+      searchScope: "remembered-collection",
+      composePlacement: "remembered-space",
+    });
+  });
+
+  it.each([
+    "/inbox",
+    "/setting",
+    "/views",
+    "/about",
+    "/memos/abc",
+    "/memos/shares/token",
+    "/403",
+    "/404",
+    "/unknown",
+  ])("sends search to All and makes Compose unassigned on %s", (path) => {
+    expect(getRouteActionPolicy(path)).toEqual({
+      searchScope: "all",
+      searchDestination: "/",
+      composePlacement: "unassigned",
+    });
+  });
 });
--- a/web/tests/attachment-library-source-link.test.tsx
+++ b/web/tests/attachment-library-source-link.test.tsx
@ -1,6 +1,6 @@
 import { create } from "@bufbuild/protobuf";
 import { fireEvent, render, screen } from "@testing-library/react";
-import { MemoryRouter } from "react-router-dom";
+import { MemoryRouter, useLocation } from "react-router-dom";
 import { describe, expect, it, vi } from "vitest";
 import AttachmentMediaGrid from "@/components/AttachmentLibrary/AttachmentMediaGrid";
 import type { AttachmentLibraryMonthGroup } from "@/hooks/useAttachmentLibrary";
@ -8,6 +8,11 @@ import { AttachmentSchema, MediaMetadataSchema, VideoMetadataSchema } from "@/ty

 vi.mock("@/utils/i18n", () => ({ useTranslate: () => (key: string) => key }));

+const LocationStateProbe = () => {
+  const location = useLocation();
+  return <output data-testid="location-state">{JSON.stringify(location.state)}</output>;
+};
+
 describe("<AttachmentMediaGrid>", () => {
  it("links a media attachment to its source memo without replacing the direct file action", () => {
    const attachment = create(AttachmentSchema, {
@ -47,8 +52,9 @@ describe("<AttachmentMediaGrid>", () => {
    const onPreview = vi.fn();

    render(
-      <MemoryRouter>
+      <MemoryRouter initialEntries={["/attachments"]}>
        <AttachmentMediaGrid groups={groups} onPreview={onPreview} />
+        <LocationStateProbe />
      </MemoryRouter>,
    );

@ -61,6 +67,7 @@ describe("<AttachmentMediaGrid>", () => {

    fireEvent.click(memoLink);
    expect(onPreview).not.toHaveBeenCalled();
+    expect(screen.getByTestId("location-state")).toHaveTextContent('{"from":"/","fromScope":"preserve"}');
  });

  it("keeps video duration inside the existing play badge", () => {
--- a/web/tests/attachment-library-stats.test.ts
+++ b/web/tests/attachment-library-stats.test.ts
@ -76,7 +76,21 @@ describe("buildAttachmentLibraryStats", () => {
    expect(clients.listAttachments.mock.calls.map(([request]) => request.filter)).toEqual([filter, filter]);
  });

-  it("combines the current context with the unused attachment filter", async () => {
+  it("uses only the unused predicate in the All collection", async () => {
+    clients.listAttachments.mockResolvedValue({ attachments: [], nextPageToken: "" });
+    const queryClient = new QueryClient({ defaultOptions: { queries: { retry: false } } });
+    const wrapper = ({ children }: PropsWithChildren) => createElement(QueryClientProvider, { client: queryClient }, children);
+    const { result } = renderHook(() => useUnusedAttachmentLibrary("en", undefined), { wrapper });
+
+    await waitFor(() => expect(result.current.isComplete).toBe(true));
+    expect(clients.listAttachments).toHaveBeenCalledWith(
+      expect.objectContaining({
+        filter: "(memo_id == null)",
+      }),
+    );
+  });
+
+  it("combines an explicit unassigned filter with the unused attachment predicate", async () => {
    clients.listAttachments.mockResolvedValue({ attachments: [], nextPageToken: "" });
    const queryClient = new QueryClient({ defaultOptions: { queries: { retry: false } } });
    const wrapper = ({ children }: PropsWithChildren) => createElement(QueryClientProvider, { client: queryClient }, children);
--- a/web/tests/filtered-memo-stats.test.ts
+++ b/web/tests/filtered-memo-stats.test.ts
@ -145,7 +145,7 @@ describe("useFilteredMemoStats", () => {
    });
    const filter = 'space == "spaces/product"';

-    renderHook(() => useFilteredMemoStats({ context: "explore", filter, includeSpaceVisibility: true }), { wrapper });
+    renderHook(() => useFilteredMemoStats({ context: "explore", filter }), { wrapper });

    expect(useAllUserStats).toHaveBeenCalledWith(
      {
@ -156,7 +156,26 @@ describe("useFilteredMemoStats", () => {
    );
  });

-  it("uses the no-Space filter for Memos statistics", () => {
+  it("includes authorized Space memos in All Explore statistics", () => {
+    mockUseView.mockReturnValue({
+      timeBasis: "create_time",
+      orderByTimeAsc: false,
+      setOrderByTimeAsc: vi.fn(),
+      setTimeBasis: vi.fn(),
+    });
+
+    renderHook(() => useFilteredMemoStats({ context: "explore" }), { wrapper });
+
+    expect(useAllUserStats).toHaveBeenCalledWith(
+      {
+        state: State.NORMAL,
+        filter: '(visibility in ["PUBLIC", "PROTECTED", "SPACE"])',
+      },
+      { enabled: true },
+    );
+  });
+
+  it("supports an explicit unassigned filter", () => {
    mockUseView.mockReturnValue({
      timeBasis: "create_time",
      orderByTimeAsc: false,
--- a/web/tests/global-memo-editor.test.tsx
+++ b/web/tests/global-memo-editor.test.tsx
@ -14,6 +14,12 @@ const mocks = vi.hoisted(() => ({
  setMobileOpen: vi.fn(),
  setQuickFindOpen: vi.fn(),
  selectedSpaceName: undefined as string | undefined,
+  pathname: "/",
+}));
+
+vi.mock("react-router-dom", async (importOriginal) => ({
+  ...(await importOriginal<typeof import("react-router-dom")>()),
+  useLocation: () => ({ pathname: mocks.pathname }),
 }));

 vi.mock("@/components/MemoEditor/loader", () => ({
@ -117,6 +123,7 @@ describe("GlobalMemoEditorProvider", () => {
    mocks.setMobileOpen.mockClear();
    mocks.setQuickFindOpen.mockClear();
    mocks.selectedSpaceName = undefined;
+    mocks.pathname = "/";
  });

  it("opens a modal focus-mode editor, closes the sidebar surfaces, and restores focus after Escape", async () => {
@ -276,4 +283,37 @@ describe("GlobalMemoEditorProvider", () => {
      defaultSpace: "spaces/product",
    });
  });
+
+  it.each(["/explore", "/archived", "/attachments"])("inherits the remembered Space when composing from %s", async (pathname) => {
+    mocks.pathname = pathname;
+    mocks.selectedSpaceName = "spaces/product";
+    await openViaTrigger();
+
+    expect(mocks.editorProps).toMatchObject({
+      cacheKey: "global-memo-editor:spaces/product",
+      defaultSpace: "spaces/product",
+    });
+  });
+
+  it.each([
+    "/u/steven",
+    "/inbox",
+    "/setting",
+    "/views",
+    "/about",
+    "/memos/abc",
+    "/memos/shares/token",
+    "/403",
+    "/404",
+    "/unknown",
+  ])("creates an unassigned memo from %s even when a Space is remembered", async (pathname) => {
+    mocks.pathname = pathname;
+    mocks.selectedSpaceName = "spaces/product";
+    await openViaTrigger();
+
+    expect(mocks.editorProps).toMatchObject({
+      cacheKey: "global-memo-editor",
+      defaultSpace: undefined,
+    });
+  });
 });
--- a/web/tests/home-loading-boundary.test.tsx
+++ b/web/tests/home-loading-boundary.test.tsx
@ -54,7 +54,7 @@ vi.mock("@/contexts/NewMemoContext", () => ({
 vi.mock("@/contexts/SpaceContext", () => ({
  useSpaceContext: () => ({
    selectedSpaceName: state.selectedSpaceName,
-    memoFilter: state.selectedSpaceName ? `space == "${state.selectedSpaceName}"` : "space == null",
+    memoFilter: state.selectedSpaceName ? `space == "${state.selectedSpaceName}"` : undefined,
  }),
 }));

@ -78,7 +78,8 @@ describe("<Home>", () => {

    expect(screen.getByTestId("memo-editor")).toBeInTheDocument();
    expect(screen.getByTestId("memo-view")).toBeInTheDocument();
-    expect(state.listProps).toMatchObject({ contextFilter: "space == null" });
+    expect(state.listProps).toMatchObject({ contextFilter: undefined });
+    expect(state.editorProps).toMatchObject({ cacheKey: "home-memo-editor", defaultSpace: undefined });
  });

  it("filters the feed and sets new memo placement to the selected Space", () => {
--- a/web/tests/memo-action-navigation.test.tsx
+++ b/web/tests/memo-action-navigation.test.tsx
@ -0,0 +1,115 @@
+import { QueryClient, QueryClientProvider } from "@tanstack/react-query";
+import { act, renderHook, waitFor } from "@testing-library/react";
+import type { ReactNode } from "react";
+import { MemoryRouter, useLocation } from "react-router-dom";
+import { beforeEach, describe, expect, it, vi } from "vitest";
+import { useMemoActionHandlers } from "@/components/MemoActionMenu/hooks";
+import type { MemoOriginScope } from "@/components/MemoView/navigation";
+import { State } from "@/types/proto/api/v1/common_pb";
+import type { Memo } from "@/types/proto/api/v1/memo_service_pb";
+
+const mocks = vi.hoisted(() => ({
+  updateMemo: vi.fn(),
+  deleteMemo: vi.fn(),
+  clearSelectedSpace: vi.fn(),
+}));
+
+vi.mock("@/hooks/useMemoQueries", () => ({
+  memoKeys: { comments: (name: string) => ["memos", name, "comments"] },
+  useUpdateMemo: () => ({ mutateAsync: mocks.updateMemo }),
+  useDeleteMemo: () => ({ mutateAsync: mocks.deleteMemo }),
+}));
+
+vi.mock("@/hooks/useUserQueries", () => ({
+  userKeys: { stats: () => ["users", "stats"] },
+}));
+
+vi.mock("@/contexts/InstanceContext", () => ({
+  useInstance: () => ({ profile: { instanceUrl: "" } }),
+}));
+
+vi.mock("@/contexts/SpaceContext", () => ({
+  useSpaceContext: () => ({ clearSelectedSpace: mocks.clearSelectedSpace }),
+}));
+
+vi.mock("@/utils/i18n", () => ({
+  useTranslate: () => (key: string) => key,
+}));
+
+vi.mock("react-hot-toast", () => ({
+  default: { success: vi.fn(), error: vi.fn() },
+}));
+
+const createMemo = (state: State): Memo =>
+  ({
+    name: "memos/1",
+    content: "memo",
+    state,
+    parent: "",
+  }) as Memo;
+
+const renderActions = (state: State, parentScope: MemoOriginScope) => {
+  const queryClient = new QueryClient({ defaultOptions: { queries: { retry: false } } });
+  const wrapper = ({ children }: { children: ReactNode }) => (
+    <QueryClientProvider client={queryClient}>
+      <MemoryRouter initialEntries={["/memos/1"]}>{children}</MemoryRouter>
+    </QueryClientProvider>
+  );
+
+  return renderHook(
+    () => {
+      const location = useLocation();
+      const handlers = useMemoActionHandlers({
+        memo: createMemo(state),
+        parentScope,
+        setDeleteDialogOpen: vi.fn(),
+      });
+      return { handlers, pathname: location.pathname };
+    },
+    { wrapper },
+  );
+};
+
+describe("Memo detail mutation navigation", () => {
+  beforeEach(() => {
+    mocks.updateMemo.mockReset().mockResolvedValue(undefined);
+    mocks.deleteMemo.mockReset().mockResolvedValue(undefined);
+    mocks.clearSelectedSpace.mockReset();
+  });
+
+  it.each([
+    [State.NORMAL, "/archived"],
+    [State.ARCHIVED, "/"],
+  ])("switches an All-origin %s memo to the global destination", async (state, destination) => {
+    const { result } = renderActions(state, "all");
+
+    await act(async () => {
+      await result.current.handlers.handleToggleMemoStatusClick();
+    });
+
+    await waitFor(() => expect(result.current.pathname).toBe(destination));
+    expect(mocks.clearSelectedSpace).toHaveBeenCalledOnce();
+  });
+
+  it("preserves an exact-Space origin when archiving", async () => {
+    const { result } = renderActions(State.NORMAL, "preserve");
+
+    await act(async () => {
+      await result.current.handlers.handleToggleMemoStatusClick();
+    });
+
+    await waitFor(() => expect(result.current.pathname).toBe("/archived"));
+    expect(mocks.clearSelectedSpace).not.toHaveBeenCalled();
+  });
+
+  it("clears a stale Space before deleting from an All origin", async () => {
+    const { result } = renderActions(State.NORMAL, "all");
+
+    await act(async () => {
+      await result.current.handlers.confirmDeleteMemo();
+    });
+
+    await waitFor(() => expect(result.current.pathname).toBe("/"));
+    expect(mocks.clearSelectedSpace).toHaveBeenCalledOnce();
+  });
+});
--- a/web/tests/memo-content-footnotes.test.tsx
+++ b/web/tests/memo-content-footnotes.test.tsx
@ -7,10 +7,15 @@ const FOOTNOTE_MARKDOWN = "A statement with a note.[^1]\n\n[^1]: The footnote bo

 const LocationProbe = () => {
  const location = useLocation();
-  return <output data-testid="location">{`${location.pathname}${location.hash}`}</output>;
+  return (
+    <>
+      <output data-testid="location">{`${location.pathname}${location.hash}`}</output>
+      <output data-testid="origin">{typeof location.state?.from === "string" ? location.state.from : ""}</output>
+    </>
+  );
 };

-const renderFootnote = (compact = false) =>
+const renderFootnote = (compact = false, parentPage?: string) =>
  render(
    <MemoryRouter>
      <div data-memo-content>
@ -18,6 +23,8 @@ const renderFootnote = (compact = false) =>
          content={FOOTNOTE_MARKDOWN}
          resolvedMentionUsernames={new Set()}
          memoName="memos/abc123"
+          parentPage={parentPage}
+          parentScope={parentPage ? "preserve" : undefined}
          compact={compact}
        />
      </div>
@ -62,11 +69,12 @@ describe("memo footnotes", () => {
  });

  it("navigates compact cards to the memo detail footnote", () => {
-    const { container } = renderFootnote(true);
+    const { container } = renderFootnote(true, "/archived?filter=tagSearch%3Awork");
    const reference = container.querySelector<HTMLAnchorElement>("a[data-footnote-ref]");

    fireEvent.click(reference!);

    expect(screen.getByTestId("location")).toHaveTextContent("/memos/abc123#user-content-fn-1");
+    expect(screen.getByTestId("origin")).toHaveTextContent("/archived?filter=tagSearch%3Awork");
  });
 });
--- a/web/tests/memo-header-navigation.test.tsx
+++ b/web/tests/memo-header-navigation.test.tsx
@ -0,0 +1,127 @@
+import { fireEvent, render, screen } from "@testing-library/react";
+import { MemoryRouter, useLocation } from "react-router-dom";
+import { beforeEach, describe, expect, it, vi } from "vitest";
+import MemoHeader from "@/components/MemoView/components/MemoHeader";
+
+const state = vi.hoisted(() => ({
+  creator: undefined as { username: string; displayName: string; avatarUrl: string } | undefined,
+}));
+
+vi.mock("@/components/RelativeTime", () => ({
+  default: () => <>time</>,
+}));
+
+vi.mock("@/components/MemoActionMenu", () => ({
+  default: () => null,
+}));
+
+vi.mock("@/components/MemoReactionListView", () => ({
+  ReactionSelector: () => null,
+}));
+
+vi.mock("@/components/UserAvatar", () => ({
+  default: () => <span>avatar</span>,
+}));
+
+vi.mock("@/components/MemoView/components/MemoSpaceBadge", () => ({
+  default: ({ spaceName }: { spaceName?: string }) => <span data-testid="memo-space">{spaceName}</span>,
+}));
+
+vi.mock("@/components/ui/tooltip", () => ({
+  Tooltip: ({ children }: { children: React.ReactNode }) => <>{children}</>,
+  TooltipProvider: ({ children }: { children: React.ReactNode }) => <>{children}</>,
+  TooltipTrigger: ({ children, render }: { children?: React.ReactNode; render?: React.ReactNode }) => <>{render || children}</>,
+  TooltipContent: () => null,
+}));
+
+vi.mock("@/contexts/NewMemoContext", () => ({
+  useNewMemo: () => ({ newMemoName: undefined }),
+}));
+
+vi.mock("@/i18n", () => ({
+  default: { language: "en" },
+}));
+
+vi.mock("@/components/MemoView/hooks", () => ({
+  useMemoActions: () => ({ unpinMemo: vi.fn() }),
+}));
+
+vi.mock("@/components/MemoView/MemoViewContext", () => ({
+  useMemoViewContext: () => ({
+    memo: { name: "memos/123", visibility: 1, pinned: false, space: "spaces/product" },
+    creator: state.creator,
+    currentUser: undefined,
+    parentPage: "/explore?filter=tagSearch%3Awork",
+    parentScope: "preserve",
+    isArchived: false,
+    readonly: false,
+    openEditor: vi.fn(),
+  }),
+  useMemoViewDerived: () => ({
+    createTime: new Date("2026-08-26T00:00:00Z"),
+    updateTime: undefined,
+    displayTime: new Date("2026-08-26T00:00:00Z"),
+    isDisplayingUpdatedTime: false,
+    relativeTimeFormat: "auto",
+  }),
+}));
+
+vi.mock("@/utils/i18n", () => ({
+  useTranslate: () => (key: string) => key,
+}));
+
+const LocationProbe = () => {
+  const location = useLocation();
+  return (
+    <output data-testid="location">
+      {location.pathname}|{JSON.stringify(location.state)}
+    </output>
+  );
+};
+
+describe("MemoHeader navigation", () => {
+  beforeEach(() => {
+    state.creator = undefined;
+  });
+
+  it.each([false, true])("uses a keyboard-operable timestamp and preserves origin when showCreator=%s", (showCreator) => {
+    if (showCreator) {
+      state.creator = { username: "alice", displayName: "Alice", avatarUrl: "" };
+    }
+
+    render(
+      <MemoryRouter initialEntries={["/explore?filter=tagSearch%3Awork"]}>
+        <MemoHeader showCreator={showCreator} />
+        <LocationProbe />
+      </MemoryRouter>,
+    );
+
+    const timestamp = screen.getByRole("button", { name: "time" });
+    timestamp.focus();
+    expect(timestamp).toHaveFocus();
+
+    fireEvent.click(timestamp);
+    expect(screen.getByTestId("location")).toHaveTextContent(
+      '/memos/123|{"from":"/explore?filter=tagSearch%3Awork","fromScope":"preserve"}',
+    );
+  });
+
+  it.each([false, true])("keeps the Space pill beside the timestamp when showCreator=%s", (showCreator) => {
+    if (showCreator) {
+      state.creator = { username: "alice", displayName: "Alice", avatarUrl: "" };
+    }
+
+    render(
+      <MemoryRouter>
+        <MemoHeader showCreator={showCreator} showSpace />
+      </MemoryRouter>,
+    );
+
+    const timestamp = screen.getByRole("button", { name: "time" });
+    const space = screen.getByTestId("memo-space");
+    const metadata = space.closest('[data-slot="memo-header-meta"]');
+
+    expect(metadata).toContainElement(timestamp);
+    expect(space.closest("a, button")).toBeNull();
+  });
+});
--- a/web/tests/memo-space-badge.test.tsx
+++ b/web/tests/memo-space-badge.test.tsx
@ -0,0 +1,49 @@
+import { render, screen } from "@testing-library/react";
+import { beforeEach, describe, expect, it, vi } from "vitest";
+import MemoSpaceBadge from "@/components/MemoView/components/MemoSpaceBadge";
+
+const state = vi.hoisted(() => ({
+  spaces: [] as Array<{ name: string; title: string }>,
+}));
+
+vi.mock("@/contexts/SpaceContext", () => ({
+  useSpaceContext: () => ({ spaces: state.spaces }),
+}));
+
+vi.mock("@/utils/i18n", () => ({
+  useTranslate: () => (key: string) => (key === "space.current" ? "Space" : key),
+}));
+
+describe("MemoSpaceBadge", () => {
+  beforeEach(() => {
+    state.spaces = [];
+  });
+
+  it("shows the title of a known Space", () => {
+    state.spaces = [{ name: "spaces/product", title: "Product" }];
+    render(<MemoSpaceBadge spaceName="spaces/product" />);
+
+    expect(screen.getByTitle("Space: Product")).toHaveTextContent("Space: Product");
+  });
+
+  it("uses the shared pill presentation", () => {
+    state.spaces = [{ name: "spaces/product", title: "Product" }];
+    render(<MemoSpaceBadge spaceName="spaces/product" />);
+
+    const badge = screen.getByTitle("Space: Product");
+    expect(badge).toHaveAttribute("data-slot", "badge");
+    expect(badge.querySelector(".lucide-user-lock")).not.toBeNull();
+  });
+
+  it("uses a neutral label rather than fetching or exposing an unknown Space", () => {
+    render(<MemoSpaceBadge spaceName="spaces/private" />);
+
+    expect(screen.getByTitle("Space")).toHaveTextContent("Space");
+    expect(screen.queryByText("spaces/private")).not.toBeInTheDocument();
+  });
+
+  it("omits placement for an unassigned memo", () => {
+    const { container } = render(<MemoSpaceBadge />);
+    expect(container).toBeEmptyDOMElement();
+  });
+});
--- a/web/tests/memo-tag-navigation.test.tsx
+++ b/web/tests/memo-tag-navigation.test.tsx
@ -0,0 +1,76 @@
+import { fireEvent, render, screen } from "@testing-library/react";
+import { MemoryRouter } from "react-router-dom";
+import { beforeEach, describe, expect, it, vi } from "vitest";
+import { Tag } from "@/components/MemoContent/Tag";
+
+const navigateTo = vi.hoisted(() => vi.fn());
+const clearSelectedSpace = vi.hoisted(() => vi.fn());
+const origin = vi.hoisted(() => ({
+  parentPage: "/" as string,
+  parentScope: "all" as "all" | "preserve",
+}));
+
+vi.mock("@/hooks/useNavigateTo", () => ({
+  default: () => navigateTo,
+}));
+
+vi.mock("@/components/MemoView/MemoViewContext", () => ({
+  useMemoViewContext: () => origin,
+}));
+
+vi.mock("@/contexts/SpaceContext", () => ({
+  useSpaceContext: () => ({ clearSelectedSpace }),
+}));
+
+vi.mock("@/contexts/MemoFilterContext", async (importOriginal) => {
+  const actual = await importOriginal<typeof import("@/contexts/MemoFilterContext")>();
+  return {
+    ...actual,
+    useMemoFilterContext: () => ({
+      getFiltersByFactor: () => [],
+      removeFilter: vi.fn(),
+      addFilter: vi.fn(),
+    }),
+  };
+});
+
+vi.mock("@/contexts/AuthContext", () => ({
+  useAuth: () => ({ userTagsSetting: undefined }),
+}));
+
+describe("Memo tag navigation", () => {
+  beforeEach(() => {
+    navigateTo.mockClear();
+    clearSelectedSpace.mockClear();
+    origin.parentPage = "/";
+    origin.parentScope = "all";
+  });
+
+  it("switches to All only when a global detail tag enters a collection", () => {
+    render(
+      <MemoryRouter initialEntries={["/memos/parent"]}>
+        <Tag data-tag="work">#work</Tag>
+      </MemoryRouter>,
+    );
+
+    fireEvent.click(screen.getByText("#work"));
+
+    expect(clearSelectedSpace).toHaveBeenCalledOnce();
+    expect(navigateTo).toHaveBeenCalledWith("/?filter=tagSearch%3Awork");
+  });
+
+  it("returns a Profile-origin tag without clearing the remembered Space", () => {
+    origin.parentPage = "/u/alice?view=map";
+
+    render(
+      <MemoryRouter initialEntries={["/memos/parent"]}>
+        <Tag data-tag="work">#work</Tag>
+      </MemoryRouter>,
+    );
+
+    fireEvent.click(screen.getByText("#work"));
+
+    expect(clearSelectedSpace).not.toHaveBeenCalled();
+    expect(navigateTo).toHaveBeenCalledWith("/u/alice?filter=tagSearch%3Awork");
+  });
+});
--- a/web/tests/memo-view-navigation.test.ts
+++ b/web/tests/memo-view-navigation.test.ts
@ -0,0 +1,127 @@
+import { describe, expect, it } from "vitest";
+import {
+  createMemoNavigationState,
+  isMemoCollectionOrigin,
+  isMemoDetailPath,
+  isMemoResourcePath,
+  resolveMemoDetailOrigin,
+  resolveMemoOrigin,
+  resolveMemoParentPage,
+  withMemoFilter,
+} from "@/components/MemoView/navigation";
+
+describe("memo view navigation", () => {
+  it("captures the complete collection origin", () => {
+    expect(
+      resolveMemoParentPage({
+        pathname: "/archived",
+        search: "?filter=tagSearch%3Awork",
+        memoName: "memos/123",
+      }),
+    ).toBe("/archived?filter=tagSearch%3Awork");
+  });
+
+  it("keeps an explicit origin on a canonical memo route", () => {
+    expect(
+      resolveMemoParentPage({
+        explicitParentPage: "/explore?filter=contentSearch%3Aroadmap",
+        pathname: "/memos/123",
+        search: "",
+        memoName: "memos/123",
+      }),
+    ).toBe("/explore?filter=contentSearch%3Aroadmap");
+  });
+
+  it("marks collection cards as preserving the remembered scope", () => {
+    expect(resolveMemoOrigin({ pathname: "/explore", search: "?filter=tagSearch%3Awork", memoName: "memos/123" })).toEqual({
+      parentPage: "/explore?filter=tagSearch%3Awork",
+      parentScope: "preserve",
+    });
+  });
+
+  it("marks Profile cards as global without losing their Profile origin", () => {
+    expect(resolveMemoOrigin({ pathname: "/u/alice", search: "?view=map", memoName: "memos/123" })).toEqual({
+      parentPage: "/u/alice?view=map",
+      parentScope: "all",
+    });
+  });
+
+  it("uses an All Home origin for direct and shared resource entries", () => {
+    expect(resolveMemoDetailOrigin(undefined)).toEqual({ parentPage: "/", parentScope: "all" });
+    expect(resolveMemoDetailOrigin({ unrelated: true })).toEqual({ parentPage: "/", parentScope: "all" });
+  });
+
+  it("uses an All Archived origin for a direct archived memo", () => {
+    expect(resolveMemoDetailOrigin(undefined, { memoArchived: true })).toEqual({ parentPage: "/archived", parentScope: "all" });
+  });
+
+  it("keeps an explicit origin ahead of the archived fallback", () => {
+    expect(resolveMemoDetailOrigin(createMemoNavigationState("/u/alice", "all"), { memoArchived: true })).toEqual({
+      parentPage: "/u/alice",
+      parentScope: "all",
+    });
+  });
+
+  it("round-trips an explicit origin policy through router state", () => {
+    const state = createMemoNavigationState("/", "preserve");
+    expect(resolveMemoDetailOrigin(state)).toEqual({ parentPage: "/", parentScope: "preserve" });
+  });
+
+  it("infers policy for legacy from-only router state", () => {
+    expect(resolveMemoDetailOrigin({ from: "/archived" })).toEqual({ parentPage: "/archived", parentScope: "preserve" });
+    expect(resolveMemoDetailOrigin({ from: "/u/alice" })).toEqual({ parentPage: "/u/alice", parentScope: "all" });
+  });
+
+  it.each([
+    "/",
+    "/explore?filter=tagSearch%3Awork",
+    "/archived",
+    "/attachments",
+  ])("recognizes %s as a remembered collection origin", (page) => {
+    expect(isMemoCollectionOrigin(page)).toBe(true);
+  });
+
+  it.each([
+    "/memos/123",
+    "/memos/123/",
+    "/Memos/123",
+    "/memos/shares/token",
+    "/Memos/Shares/token/",
+  ])("does not treat %s as its own origin", (pathname) => {
+    expect(isMemoDetailPath(pathname, "memos/123")).toBe(true);
+    expect(resolveMemoParentPage({ pathname, search: "", memoName: "memos/123" })).toBe("/");
+  });
+
+  it("does not confuse a different memo route with the current memo detail", () => {
+    const pathname = "/memos/1234";
+    expect(isMemoDetailPath(pathname, "memos/123")).toBe(false);
+    expect(resolveMemoParentPage({ pathname, search: "", memoName: "memos/123" })).toBe(pathname);
+  });
+
+  it("rejects extra path segments after a share token", () => {
+    expect(isMemoDetailPath("/memos/shares/token/extra", "memos/123")).toBe(false);
+  });
+
+  it.each([
+    "/memos/123",
+    "/Memos/123/",
+    "/memos/shares/token",
+    "/Memos/Shares/token/",
+  ])("recognizes %s as a Memo resource route", (pathname) => {
+    expect(isMemoResourcePath(pathname)).toBe(true);
+  });
+
+  it.each(["/", "/memos", "/memos/123/extra", "/memos/shares/token/extra"])("rejects %s as a Memo resource route", (pathname) => {
+    expect(isMemoResourcePath(pathname)).toBe(false);
+  });
+
+  it("replaces the filter without dropping other origin query parameters", () => {
+    expect(withMemoFilter("/u/alice?view=memos&filter=old#section", "tagSearch:design")).toBe(
+      "/u/alice?view=memos&filter=tagSearch%3Adesign",
+    );
+  });
+
+  it("returns a Profile map origin to its memo list when applying a filter", () => {
+    expect(withMemoFilter("/u/alice?view=map", "tagSearch:design")).toBe("/u/alice?filter=tagSearch%3Adesign");
+  });
+});
--- a/web/tests/quick-find-navigation.test.tsx
+++ b/web/tests/quick-find-navigation.test.tsx
@ -0,0 +1,143 @@
+import { act, fireEvent, render, screen, waitFor } from "@testing-library/react";
+import { createMemoryRouter, RouterProvider, useLocation } from "react-router-dom";
+import { beforeEach, describe, expect, it, vi } from "vitest";
+import QuickFindDialog from "@/components/AppSidebar/QuickFindDialog";
+import { AppSidebarProvider, useAppSidebar } from "@/contexts/AppSidebarContext";
+import { getSelectedSpaceStorageKey, SpaceProvider, useSpaceContext } from "@/contexts/SpaceContext";
+
+const state = vi.hoisted(() => ({
+  currentUser: { name: "users/alice" } as { name: string } | undefined,
+  spaces: [{ name: "spaces/product", title: "Product", description: "" }],
+  filters: [] as Array<{ factor: "contentSearch"; value: string }>,
+  setFilters: vi.fn(),
+  setMemoView: vi.fn(),
+}));
+
+vi.mock("@/contexts/MemoFilterContext", async (importOriginal) => {
+  const actual = await importOriginal<typeof import("@/contexts/MemoFilterContext")>();
+  return {
+    ...actual,
+    useMemoFilterContext: () => ({
+      filters: state.filters,
+      memoView: undefined,
+      setFilters: state.setFilters,
+      setMemoView: state.setMemoView,
+    }),
+  };
+});
+
+vi.mock("@/hooks/useCurrentUser", () => ({
+  default: () => state.currentUser,
+}));
+
+vi.mock("@/hooks/useSpaceQueries", () => ({
+  useSpaces: () => ({ data: state.spaces, isSuccess: true, isPending: false, isError: false }),
+}));
+
+vi.mock("@/hooks/useUserQueries", () => ({
+  useMemoViews: () => ({ data: [] }),
+}));
+
+vi.mock("@/utils/i18n", () => ({
+  useTranslate: () => (key: string) => key,
+}));
+
+const Harness = () => {
+  const location = useLocation();
+  const { setQuickFindOpen } = useAppSidebar();
+  const { collectionScope } = useSpaceContext();
+
+  return (
+    <>
+      <output data-testid="path">{`${location.pathname}${location.search}`}</output>
+      <output data-testid="scope">{collectionScope.kind === "space" ? collectionScope.name : collectionScope.kind}</output>
+      <button type="button" onClick={() => setQuickFindOpen(true)}>
+        Open Quick Find
+      </button>
+      <QuickFindDialog />
+    </>
+  );
+};
+
+describe("Quick Find navigation", () => {
+  beforeEach(() => {
+    sessionStorage.clear();
+    state.currentUser = { name: "users/alice" };
+    state.filters = [];
+    state.setFilters.mockClear();
+    state.setMemoView.mockClear();
+  });
+
+  it("switches to All in one history step so Back returns directly to Inbox", async () => {
+    const storageKey = getSelectedSpaceStorageKey("users/alice");
+    sessionStorage.setItem(storageKey, "spaces/product");
+
+    const router = createMemoryRouter(
+      [
+        {
+          path: "*",
+          element: (
+            <SpaceProvider>
+              <AppSidebarProvider>
+                <Harness />
+              </AppSidebarProvider>
+            </SpaceProvider>
+          ),
+        },
+      ],
+      { initialEntries: ["/inbox"] },
+    );
+    render(<RouterProvider router={router} />);
+
+    expect(screen.getByTestId("scope")).toHaveTextContent("spaces/product");
+    fireEvent.click(screen.getByRole("button", { name: "Open Quick Find" }));
+    const input = await screen.findByRole("textbox");
+    fireEvent.change(input, { target: { value: "roadmap" } });
+    fireEvent.submit(input.closest("form")!);
+
+    await waitFor(() => expect(screen.getByTestId("path")).toHaveTextContent("/?filter=contentSearch:roadmap"));
+    expect(state.setFilters).toHaveBeenCalledWith([{ factor: "contentSearch", value: "roadmap" }]);
+    expect(screen.getByTestId("scope")).toHaveTextContent("all");
+    expect(sessionStorage.getItem(storageKey)).toBeNull();
+
+    await act(async () => {
+      await router.navigate(-1);
+    });
+
+    expect(screen.getByTestId("path")).toHaveTextContent("/inbox");
+  });
+
+  it("preserves an anonymous global page in history", async () => {
+    state.currentUser = undefined;
+
+    const router = createMemoryRouter(
+      [
+        {
+          path: "*",
+          element: (
+            <SpaceProvider>
+              <AppSidebarProvider>
+                <Harness />
+              </AppSidebarProvider>
+            </SpaceProvider>
+          ),
+        },
+      ],
+      { initialEntries: ["/about"] },
+    );
+    render(<RouterProvider router={router} />);
+
+    fireEvent.click(screen.getByRole("button", { name: "Open Quick Find" }));
+    const input = await screen.findByRole("textbox");
+    fireEvent.change(input, { target: { value: "roadmap" } });
+    fireEvent.submit(input.closest("form")!);
+
+    await waitFor(() => expect(screen.getByTestId("path")).toHaveTextContent("/?filter=contentSearch:roadmap"));
+
+    await act(async () => {
+      await router.navigate(-1);
+    });
+
+    expect(screen.getByTestId("path")).toHaveTextContent("/about");
+  });
+});
--- a/web/tests/quick-find.test.ts
+++ b/web/tests/quick-find.test.ts
@ -1,5 +1,5 @@
 import { describe, expect, it } from "vitest";
-import { buildQuickFindFilters, isQuickFindCollectionRoute } from "@/components/AppSidebar/QuickFindDialog";
+import { buildQuickFindFilters, resolveQuickFindSubmission } from "@/components/AppSidebar/QuickFindDialog";
 import { type MemoFilter, replaceFiltersByFactor } from "@/contexts/MemoFilterContext";

 describe("Quick Find", () => {
@ -20,9 +20,70 @@ describe("Quick Find", () => {

  it("starts a clean All search outside collection routes", () => {
    expect(buildQuickFindFilters("project", scopedFilters, false)).toEqual([{ factor: "contentSearch", value: "project" }]);
-    expect(isQuickFindCollectionRoute("/attachments")).toBe(false);
-    expect(isQuickFindCollectionRoute("/archived")).toBe(true);
-    expect(isQuickFindCollectionRoute("/u/steven")).toBe(true);
+  });
+
+  it.each(["/", "/explore", "/archived"])("keeps scoped filters and stays on %s", (pathname) => {
+    expect(resolveQuickFindSubmission(pathname, "project", scopedFilters)).toEqual({
+      filters: [
+        { factor: "tagSearch", value: "work" },
+        { factor: "displayTime", value: "2026-08-03" },
+        { factor: "contentSearch", value: "project" },
+      ],
+      destination: undefined,
+      switchToAll: false,
+    });
+  });
+
+  it("keeps the remembered collection filters when searching from Attachments", () => {
+    expect(resolveQuickFindSubmission("/attachments", "project", scopedFilters)).toEqual({
+      filters: [
+        { factor: "tagSearch", value: "work" },
+        { factor: "displayTime", value: "2026-08-03" },
+        { factor: "contentSearch", value: "project" },
+      ],
+      destination: "/?filter=tagSearch:work,displayTime:2026-08-03,contentSearch:project",
+      switchToAll: false,
+    });
+  });
+
+  it("keeps the remembered collection on a normalized Attachments route", () => {
+    expect(resolveQuickFindSubmission("/Attachments/", "project", scopedFilters)).toEqual({
+      filters: [
+        { factor: "tagSearch", value: "work" },
+        { factor: "displayTime", value: "2026-08-03" },
+        { factor: "contentSearch", value: "project" },
+      ],
+      destination: "/?filter=tagSearch:work,displayTime:2026-08-03,contentSearch:project",
+      switchToAll: false,
+    });
+  });
+
+  it("keeps Profile search on the Profile and returns its map tab to the memo list", () => {
+    expect(resolveQuickFindSubmission("/u/steven", "project", scopedFilters)).toEqual({
+      filters: [
+        { factor: "tagSearch", value: "work" },
+        { factor: "displayTime", value: "2026-08-03" },
+        { factor: "contentSearch", value: "project" },
+      ],
+      destination: "/u/steven?filter=tagSearch:work,displayTime:2026-08-03,contentSearch:project",
+      switchToAll: false,
+    });
+  });
+
+  it.each([
+    "/inbox",
+    "/setting",
+    "/views",
+    "/about",
+    "/memos/abc",
+    "/memos/shares/token",
+    "/404",
+  ])("starts a clean All search from %s", (pathname) => {
+    expect(resolveQuickFindSubmission(pathname, "project", scopedFilters)).toEqual({
+      filters: [{ factor: "contentSearch", value: "project" }],
+      destination: "/?filter=contentSearch:project",
+      switchToAll: true,
+    });
  });

  it("replaces only the selected date facet", () => {
--- a/web/tests/space-context.test.tsx
+++ b/web/tests/space-context.test.tsx
@ -26,15 +26,22 @@ vi.mock("@/hooks/useSpaceQueries", () => ({
 }));

 const Probe = () => {
-  const { memoFilter, spaces, selectedSpace, selectedSpaceName, selectMemos, selectSpace } = useSpaceContext();
+  const { clearSelectedSpace, collectionScope, memoFilter, spaces, selectedSpace, selectedSpaceName, selectMemos, selectSpace } =
+    useSpaceContext();
  return (
    <div>
      <output data-testid="selected-name">{selectedSpaceName ?? "Memos"}</output>
      <output data-testid="selected-title">{selectedSpace?.title ?? ""}</output>
+      <output data-testid="collection-scope">
+        {collectionScope.kind === "space" ? `${collectionScope.kind}:${collectionScope.name}` : collectionScope.kind}
+      </output>
      <output data-testid="memo-filter">{memoFilter ?? "all"}</output>
      <button type="button" onClick={selectMemos}>
        Select Memos
      </button>
+      <button type="button" onClick={clearSelectedSpace}>
+        Clear Space in place
+      </button>
      <button type="button" onClick={() => spaces[0] && selectSpace(spaces[0])}>
        Select first Space
      </button>
@ -46,7 +53,10 @@ const Probe = () => {
  );
 };

-const CurrentPath = () => <output data-testid="path">{useLocation().pathname}</output>;
+const CurrentPath = () => {
+  const location = useLocation();
+  return <output data-testid="path">{`${location.pathname}${location.search}`}</output>;
+};

 const renderProvider = (initialPath = "/explore") =>
  render(
@ -64,11 +74,12 @@ describe("SpaceProvider", () => {
    state.query = { data: [], isSuccess: true, isPending: false, isError: false };
  });

-  it("uses Memos when the user has no stored Space selection", () => {
+  it("uses the All collection when the user has no stored Space selection", () => {
    renderProvider();

    expect(screen.getByTestId("selected-name")).toHaveTextContent("Memos");
-    expect(screen.getByTestId("memo-filter")).toHaveTextContent("space == null");
+    expect(screen.getByTestId("collection-scope")).toHaveTextContent("all");
+    expect(screen.getByTestId("memo-filter")).toHaveTextContent("all");
  });

  it("restores a valid Space and stores changes only for the current user", () => {
@ -79,6 +90,7 @@ describe("SpaceProvider", () => {

    expect(screen.getByTestId("selected-name")).toHaveTextContent(product.name);
    expect(screen.getByTestId("selected-title")).toHaveTextContent("Product");
+    expect(screen.getByTestId("collection-scope")).toHaveTextContent("space:spaces/product");
    expect(screen.getByTestId("memo-filter")).toHaveTextContent('space == "spaces/product"');

    fireEvent.click(screen.getByRole("button", { name: "Select Memos" }));
@ -118,29 +130,64 @@ describe("SpaceProvider", () => {
    expect(sessionStorage.getItem(getSelectedSpaceStorageKey("users/alice"))).toBe(newlyCreatedSpace.name);
  });

-  it("lands on the context's feed when switching to a Space", () => {
+  it.each([
+    "/",
+    "/explore",
+    "/archived?filter=tagSearch%3Awork",
+    "/attachments",
+  ])("preserves the current collection route when switching to a Space from %s", (initialPath) => {
    const product = { name: "spaces/product", title: "Product", description: "" };
    state.query.data = [product];
-    renderProvider("/archived");
-
-    expect(screen.getByTestId("path")).toHaveTextContent("/archived");
+    renderProvider(initialPath);

    fireEvent.click(screen.getByRole("button", { name: "Select first Space" }));

    expect(screen.getByTestId("selected-name")).toHaveTextContent(product.name);
-    expect(screen.getByTestId("path")).toHaveTextContent("/");
+    expect(screen.getByTestId("path").textContent).toBe(initialPath);
  });

-  it("returns to the Memos feed when leaving a Space, even from another route", () => {
+  it.each([
+    "/",
+    "/explore",
+    "/archived?filter=tagSearch%3Awork",
+    "/attachments",
+  ])("preserves the current collection route when switching to All from %s", (initialPath) => {
    const product = { name: "spaces/product", title: "Product", description: "" };
    state.query.data = [product];
    sessionStorage.setItem(getSelectedSpaceStorageKey("users/alice"), product.name);
-    renderProvider("/explore");
+    renderProvider(initialPath);

    fireEvent.click(screen.getByRole("button", { name: "Select Memos" }));

    expect(screen.getByTestId("selected-name")).toHaveTextContent("Memos");
-    expect(screen.getByTestId("path")).toHaveTextContent("/");
+    expect(screen.getByTestId("path").textContent).toBe(initialPath);
+  });
+
+  it.each([
+    ["Select first Space", "/inbox"],
+    ["Select Memos", "/u/alice"],
+  ])("falls back to Home when using %s outside a collection route", (action, initialPath) => {
+    const product = { name: "spaces/product", title: "Product", description: "" };
+    state.query.data = [product];
+    sessionStorage.setItem(getSelectedSpaceStorageKey("users/alice"), product.name);
+    renderProvider(initialPath);
+
+    fireEvent.click(screen.getByRole("button", { name: action }));
+
+    expect(screen.getByTestId("path").textContent).toBe("/");
+  });
+
+  it("can select All on a resource route without navigating", () => {
+    const product = { name: "spaces/product", title: "Product", description: "" };
+    state.query.data = [product];
+    sessionStorage.setItem(getSelectedSpaceStorageKey("users/alice"), product.name);
+    renderProvider("/memos/123");
+
+    fireEvent.click(screen.getByRole("button", { name: "Clear Space in place" }));
+
+    expect(screen.getByTestId("collection-scope")).toHaveTextContent("all");
+    expect(screen.getByTestId("path")).toHaveTextContent("/memos/123");
+    expect(sessionStorage.getItem(getSelectedSpaceStorageKey("users/alice"))).toBeNull();
  });

  it("isolates the active selection across account changes", () => {
--- a/web/tests/space-feed-pages.test.tsx
+++ b/web/tests/space-feed-pages.test.tsx
@ -6,19 +6,26 @@ import { Visibility } from "@/types/proto/api/v1/memo_service_pb";

 const state = vi.hoisted(() => ({
  selectedSpaceName: undefined as string | undefined,
-  memoFilter: "space == null" as string | undefined,
+  memoFilter: undefined as string | undefined,
  listProps: [] as Array<Record<string, unknown>>,
+  memoViewProps: [] as Array<Record<string, unknown>>,
  filterOptions: [] as Array<Record<string, unknown>>,
 }));

 vi.mock("@/components/MemoView", () => ({
-  default: () => <div />,
+  default: (props: Record<string, unknown>) => {
+    state.memoViewProps.push(props);
+    return <div />;
+  },
 }));

 vi.mock("@/components/PagedMemoList", () => ({
  default: (props: Record<string, unknown>) => {
    state.listProps.push(props);
-    return <div />;
+    const renderer = props.renderer as
+      | ((memo: { name: string; space: string }, options: { compact: boolean }) => React.ReactNode)
+      | undefined;
+    return <div>{renderer?.({ name: "memos/test", space: "spaces/product" }, { compact: false })}</div>;
  },
  getMemoKey: (memo: { name: string }) => memo.name,
 }));
@ -42,12 +49,13 @@ vi.mock("@/hooks/useCurrentUser", () => ({
 describe("Space-scoped feed pages", () => {
  beforeEach(() => {
    state.selectedSpaceName = undefined;
-    state.memoFilter = "space == null";
+    state.memoFilter = undefined;
    state.listProps = [];
+    state.memoViewProps = [];
    state.filterOptions = [];
  });

-  it("uses the no-Space filter for Memos Explore and Archived", () => {
+  it("uses the All collection without a Space filter for Explore and Archived", () => {
    render(
      <>
        <Explore />
@ -56,8 +64,12 @@ describe("Space-scoped feed pages", () => {
    );

    expect(state.listProps).toHaveLength(2);
-    expect(state.listProps[0]).toMatchObject({ contextFilter: "space == null" });
-    expect(state.listProps[1]).toMatchObject({ contextFilter: "space == null" });
+    expect(state.listProps[0]).toMatchObject({ contextFilter: undefined });
+    expect(state.listProps[1]).toMatchObject({ contextFilter: undefined });
+    expect(state.filterOptions[0]).toMatchObject({
+      visibilities: [Visibility.PUBLIC, Visibility.PROTECTED, Visibility.SPACE],
+    });
+    expect(state.memoViewProps).toEqual([expect.objectContaining({ showSpace: true }), expect.objectContaining({ showSpace: true })]);
  });

  it("uses the selected Space filter and includes its member audience in Explore", () => {
@ -69,5 +81,6 @@ describe("Space-scoped feed pages", () => {
    expect(state.filterOptions[0]).toMatchObject({
      visibilities: [Visibility.PUBLIC, Visibility.PROTECTED, Visibility.SPACE],
    });
+    expect(state.memoViewProps[0]).toMatchObject({ showSpace: false });
  });
 });
--- a/web/tests/user-stats-filter-queries.test.tsx
+++ b/web/tests/user-stats-filter-queries.test.tsx
@ -36,7 +36,7 @@ describe("User statistics filter queries", () => {
    expect(clients.getUserStats).toHaveBeenCalledWith({ name: "users/test", filter });
  });

-  it("sends the no-Space filter with grouped statistics", async () => {
+  it("sends an explicit unassigned filter with grouped statistics", async () => {
    const filter = "space == null";
    const { result } = renderHook(() => useAllUserStats({ state: State.ARCHIVED, filter }), { wrapper: createWrapper() });

--- a/web/tests/visibility-selector.test.tsx
+++ b/web/tests/visibility-selector.test.tsx
@ -1,14 +1,8 @@
 import { fireEvent, render, screen } from "@testing-library/react";
-import { beforeAll, beforeEach, describe, expect, it, vi } from "vitest";
+import { beforeAll, describe, expect, it, vi } from "vitest";
 import VisibilitySelector from "@/components/MemoEditor/Toolbar/VisibilitySelector";
 import { Visibility } from "@/types/proto/api/v1/memo_service_pb";

-const space = vi.hoisted(() => ({ selectedSpaceName: undefined as string | undefined }));
-
-vi.mock("@/contexts/SpaceContext", () => ({
-  useSpaceContext: () => ({ selectedSpaceName: space.selectedSpaceName }),
-}));
-
 vi.mock("@/utils/i18n", () => ({ useTranslate: () => (key: string) => key }));

 // Base UI menus reach for layout/pointer APIs jsdom doesn't implement.
@ -19,19 +13,15 @@ beforeAll(() => {
  Element.prototype.releasePointerCapture = vi.fn();
 });

-const openMenu = async (value: Visibility, onChange = vi.fn()) => {
-  render(<VisibilitySelector value={value} onChange={onChange} />);
+const openMenu = async (value: Visibility, onChange = vi.fn(), space?: string) => {
+  render(<VisibilitySelector value={value} space={space} onChange={onChange} />);
  fireEvent.click(screen.getByRole("button"));
  await screen.findByRole("menu");
  return onChange;
 };

 describe("VisibilitySelector", () => {
-  beforeEach(() => {
-    space.selectedSpaceName = undefined;
-  });
-
-  it("omits the Space audience outside a Space", async () => {
+  it("omits the Space audience when the edited memo has no Space placement", async () => {
    await openMenu(Visibility.PRIVATE);

    expect(screen.getAllByRole("menuitem").map((item) => item.textContent)).toEqual([
@ -41,21 +31,20 @@ describe("VisibilitySelector", () => {
    ]);
  });

-  it("offers the Space audience with its own description while a Space is selected", async () => {
-    space.selectedSpaceName = "spaces/product";
-    await openMenu(Visibility.PRIVATE);
+  it("offers the Space audience with its own description when the edited memo belongs to a Space", async () => {
+    await openMenu(Visibility.PRIVATE, vi.fn(), "spaces/product");

    const spaceItem = screen.getByRole("menuitem", { name: /memo\.visibility\.space/ });
    expect(spaceItem).toHaveTextContent("memo.visibility.space-description");
  });

-  it("names a Space memo's audience on the trigger even outside its Space", () => {
+  it("names the current Space audience even when placement is unavailable", () => {
    render(<VisibilitySelector value={Visibility.SPACE} onChange={vi.fn()} />);

    expect(screen.getByRole("button")).toHaveTextContent("memo.visibility.space");
  });

-  it("keeps a Space memo's own audience selectable outside its Space", async () => {
+  it("keeps the current Space audience selectable when placement is unavailable", async () => {
    await openMenu(Visibility.SPACE);

    expect(screen.getByRole("menuitem", { name: /memo\.visibility\.space/ })).toBeInTheDocument();
--- a/web/tests/visibility-space.test.tsx
+++ b/web/tests/visibility-space.test.tsx
@ -1,4 +1,5 @@
 import { render } from "@testing-library/react";
+import { UserLockIcon } from "lucide-react";
 import { describe, expect, it } from "vitest";
 import VisibilityIcon from "@/components/VisibilityIcon";
 import { Visibility } from "@/types/proto/api/v1/memo_service_pb";
@ -7,6 +8,7 @@ import {
  convertVisibilityToString,
  DEFAULT_VISIBILITY_OPTIONS,
  getAssignableVisibilityOptions,
+  getVisibilityOption,
  VISIBILITY_OPTIONS,
 } from "@/utils/memo";

@ -28,6 +30,10 @@ describe("Space visibility presentation", () => {
    expect(new Set(rendered).size).toBe(VISIBILITY_OPTIONS.length);
  });

+  it("uses user-lock for the Space audience", () => {
+    expect(getVisibilityOption(Visibility.SPACE)?.icon).toBe(UserLockIcon);
+  });
+
  it("renders nothing for an unspecified audience", () => {
    const { container } = render(<VisibilityIcon visibility={Visibility.VISIBILITY_UNSPECIFIED} />);

@ -36,16 +42,16 @@ describe("Space visibility presentation", () => {
 });

 describe("assignable visibility options", () => {
-  it("withholds the Space audience outside a Space", () => {
-    expect(values(getAssignableVisibilityOptions({ spaceSelected: false }))).toEqual([
+  it("withholds the Space audience when the memo has no Space placement", () => {
+    expect(values(getAssignableVisibilityOptions({ hasSpacePlacement: false }))).toEqual([
      Visibility.PRIVATE,
      Visibility.PROTECTED,
      Visibility.PUBLIC,
    ]);
  });

-  it("offers the Space audience while a Space is selected", () => {
-    expect(values(getAssignableVisibilityOptions({ spaceSelected: true }))).toEqual([
+  it("offers the Space audience when the memo is placed in a Space", () => {
+    expect(values(getAssignableVisibilityOptions({ hasSpacePlacement: true }))).toEqual([
      Visibility.PRIVATE,
      Visibility.SPACE,
      Visibility.PROTECTED,
@ -53,8 +59,8 @@ describe("assignable visibility options", () => {
    ]);
  });

-  it("keeps a memo's own Space audience on offer outside its Space, so picking cannot silently downgrade it", () => {
-    expect(values(getAssignableVisibilityOptions({ spaceSelected: false, current: Visibility.SPACE }))).toContain(Visibility.SPACE);
+  it("keeps a legacy Space audience on offer when placement is unavailable, so picking cannot silently downgrade it", () => {
+    expect(values(getAssignableVisibilityOptions({ hasSpacePlacement: false, current: Visibility.SPACE }))).toContain(Visibility.SPACE);
  });

  it("never offers the Space audience as a persistent default", () => {