From c82f188fc8c43c547c1787dddbf92fcbc9f02b45 Mon Sep 17 00:00:00 2001
From: Bohdan Triapitsyn <artmore@protonmail.com>
Date: Mon, 24 Aug 2026 16:36:41 +0300
Subject: [PATCH] refactor(surface): remove the main-area surface concept
 entirely
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

activeSurface was permanently 'chat' after the legacy mobile layout
removal, so the whole concept is gone: the store field, surfaceGuard,
setActiveSurface/setSurfaceGuard, the per-runtime surface memory in
prepare/restoreForRuntimeSwitch, and WorkspaceSurface itself. All ~30
setActiveSurface('chat') call sites were no-ops and are deleted;
always-true 'is the chat active' checks in keyboard shortcuts, Header
and ChatContainer are unconditional now. FilesView's dirty-file guard
kept its file-switch and close protection but drops the surface-switch
branch nothing could trigger. TerminalView visibility comes only from
its callers. The router keeps parsing legacy ?tab= links (they open the
matching context-panel surface) via its own RouteTab type and no longer
serializes a tab or diff file into URLs — desktop URLs never carried
them anyway.
---
 packages/ui/src/App.tsx                       |  2 -
 packages/ui/src/apps/runtimeEndpointReset.ts  |  3 --
 .../ui/src/components/chat/ChatContainer.tsx  |  3 +-
 packages/ui/src/components/layout/Header.tsx  | 12 +----
 .../ui/src/components/layout/MainLayout.tsx   | 11 +---
 .../session/DirectoryExplorerDialog.tsx       |  4 +-
 .../session/ScheduledTasksDialog.tsx          | 11 ++--
 .../src/components/session/SessionSidebar.tsx | 17 ++----
 .../session/SessionSwitcherDropdown.tsx       |  4 +-
 .../project-context/useProjectTodoSend.ts     |  4 +-
 .../session/sidebar/SessionGroupSection.tsx   |  8 +--
 .../session/sidebar/SidebarProjectsList.tsx   |  4 --
 .../hooks/useProjectSessionSelection.ts       |  5 --
 .../sidebar/hooks/useSessionActions.ts        |  3 --
 .../ui/src/components/ui/CommandPalette.tsx   |  5 +-
 .../ui/src/components/views/ArchiveView.tsx   |  4 +-
 .../ui/src/components/views/FilesView.tsx     | 47 ++--------------
 packages/ui/src/components/views/PlanView.tsx |  4 +-
 .../ui/src/components/views/TerminalView.tsx  |  4 +-
 .../components/views/git/ConflictDialog.tsx   |  4 --
 .../views/git/IntegrateCommitsSection.tsx     |  7 +--
 .../views/git/PullRequestSection.tsx          | 10 ++--
 packages/ui/src/hooks/useKeyboardShortcuts.ts | 25 +++------
 packages/ui/src/hooks/useMenuActions.ts       | 11 ++--
 packages/ui/src/hooks/useRouter.ts            | 24 ++-------
 packages/ui/src/lib/addSelectionToChat.ts     |  1 -
 packages/ui/src/lib/router/parseRoute.ts      |  6 +--
 .../ui/src/lib/router/serializeRoute.test.ts  |  2 -
 packages/ui/src/lib/router/serializeRoute.ts  | 17 ------
 packages/ui/src/lib/router/types.ts           |  9 ++--
 packages/ui/src/stores/useUIStore.ts          | 54 +------------------
 31 files changed, 49 insertions(+), 276 deletions(-)

diff --git a/packages/ui/src/App.tsx b/packages/ui/src/App.tsx
index c406536a..f213c11f 100644
--- a/packages/ui/src/App.tsx
+++ b/packages/ui/src/App.tsx
@@ -626,7 +626,6 @@ function App({ apis }: AppProps) {
       const directory = typeof detail?.directory === 'string' && detail.directory.trim().length > 0
         ? detail.directory.trim()
         : null;
-      useUIStore.getState().setActiveSurface('chat');
       void useSessionUIStore.getState().setCurrentSession(sessionId, directory);
     };
 
@@ -675,7 +674,6 @@ function App({ apis }: AppProps) {
         ? detail.projectId.trim()
         : null;
       const hasProjectTarget = Boolean(directory || projectId);
-      useUIStore.getState().setActiveSurface('chat');
       useUIStore.getState().setSessionSwitcherOpen(false);
       useSessionUIStore.getState().openNewSessionDraft({
         target: hasProjectTarget ? 'project' : 'chat',
diff --git a/packages/ui/src/apps/runtimeEndpointReset.ts b/packages/ui/src/apps/runtimeEndpointReset.ts
index 39c325fd..add84eb3 100644
--- a/packages/ui/src/apps/runtimeEndpointReset.ts
+++ b/packages/ui/src/apps/runtimeEndpointReset.ts
@@ -6,7 +6,6 @@ import { useProjectsStore } from '@/stores/useProjectsStore';
 import { useProjectContextStore } from '@/stores/useProjectContextStore';
 import { useGlobalSessionsStore } from '@/stores/useGlobalSessionsStore';
 import { useAutoReviewStore } from '@/stores/useAutoReviewStore';
-import { useUIStore } from '@/stores/useUIStore';
 import { usePermissionStore } from '@/stores/permissionStore';
 import { useFileSearchStore } from '@/stores/useFileSearchStore';
 import { useGitStore } from '@/stores/useGitStore';
@@ -37,7 +36,6 @@ export const reconnectAppForTransportSwitch = (): void => {
 
 export const resetAppForRuntimeEndpointChange = (detail: RuntimeEndpointChangedDetail): void => {
   useSessionUIStore.getState().prepareForRuntimeSwitch(detail.previousRuntimeKey);
-  useUIStore.getState().prepareForRuntimeSwitch(detail.previousRuntimeKey);
   if (detail.previousRuntimeKey) {
     useAutoReviewStore.getState().stopRunningRunsForRuntime(detail.previousRuntimeKey);
   }
@@ -71,7 +69,6 @@ export const resetAppForRuntimeEndpointChange = (detail: RuntimeEndpointChangedD
   useSessionFoldersStore.getState().resetForRuntimeSwitch(detail.runtimeKey);
   useFilesViewTabsStore.getState().resetForRuntimeSwitch(detail.runtimeKey);
   useSessionUIStore.getState().restoreForRuntimeSwitch(detail.runtimeKey);
-  useUIStore.getState().restoreForRuntimeSwitch(detail.runtimeKey);
   resetStreamingState();
   queueMicrotask(() => void syncDesktopSettings());
 };
diff --git a/packages/ui/src/components/chat/ChatContainer.tsx b/packages/ui/src/components/chat/ChatContainer.tsx
index e8c46c4b..a6384531 100644
--- a/packages/ui/src/components/chat/ChatContainer.tsx
+++ b/packages/ui/src/components/chat/ChatContainer.tsx
@@ -1006,8 +1006,7 @@ export const ChatContainer: React.FC<ChatContainerProps> = ({
                 return;
             }
 
-            const { activeSurface } = useUIStore.getState();
-            if (activeSurface !== 'chat' || hasBlockingChatOverlay()) {
+            if (hasBlockingChatOverlay()) {
                 return;
             }
 
diff --git a/packages/ui/src/components/layout/Header.tsx b/packages/ui/src/components/layout/Header.tsx
index 067bcd38..3d99604b 100644
--- a/packages/ui/src/components/layout/Header.tsx
+++ b/packages/ui/src/components/layout/Header.tsx
@@ -434,7 +434,6 @@ export const Header: React.FC = () => {
   const openContextOverview = useUIStore((state) => state.openContextOverview);
   const openContextPlan = useUIStore((state) => state.openContextPlan);
   const closeContextPanel = useUIStore((state) => state.closeContextPanel);
-  const activeSurface = useUIStore((state) => state.activeSurface);
   const shortcutOverrides = useUIStore((state) => state.shortcutOverrides);
 
   const getCurrentModel = useConfigStore((state) => state.getCurrentModel);
@@ -612,7 +611,6 @@ export const Header: React.FC = () => {
   }, [setWorkStatusOverlayOpen, setWorkStatusPanelEnabled, workStatusOverlayOpen, workStatusPanelEnabled, workStatusPanelFits]);
   const showDesktopHeaderContextUsage = !isVSCode
     && !workStatusPanelVisible
-    && activeSurface === 'chat'
     && !!stableDesktopContextUsage
     && stableDesktopContextUsage.totalTokens > 0;
   const desktopHeaderDisplayPercentage = stableDesktopContextUsage && stableDesktopContextUsage.contextLimit > 0
@@ -1153,9 +1151,6 @@ export const Header: React.FC = () => {
   // Reset plan tab availability when session changes
   React.useEffect(() => {
     if (!planModeEnabled) {
-      if (useUIStore.getState().activeSurface === 'plan') {
-        useUIStore.getState().setActiveSurface('chat');
-      }
       return;
     }
 
@@ -1165,11 +1160,6 @@ export const Header: React.FC = () => {
     if (lastPlanSessionKeyRef.current !== sessionKey) {
       lastPlanSessionKeyRef.current = sessionKey;
     }
-
-    // If plan is not available but user is on plan tab, switch them back to chat
-    if (!planTabAvailable && useUIStore.getState().activeSurface === 'plan') {
-      useUIStore.getState().setActiveSurface('chat');
-    }
   }, [
     planModeEnabled,
     planTabAvailable,
@@ -1759,7 +1749,7 @@ export const Header: React.FC = () => {
             className={cn(desktopHeaderIconButtonClass, 'mr-1')}
             Icon={'picture-in-picture-2'}
           />
-          {activeSurface === 'chat' && !isVSCode ? (
+          {!isVSCode ? (
             <Tooltip>
               <TooltipTrigger asChild>
                 <button
diff --git a/packages/ui/src/components/layout/MainLayout.tsx b/packages/ui/src/components/layout/MainLayout.tsx
index 094a69c6..0f30dad5 100644
--- a/packages/ui/src/components/layout/MainLayout.tsx
+++ b/packages/ui/src/components/layout/MainLayout.tsx
@@ -36,7 +36,6 @@ const SettingsWindow = lazyWithChunkRecovery(() => import('@/components/views/Se
  */
 export const MainLayout: React.FC = () => {
     const isSidebarOpen = useUIStore((state) => state.isSidebarOpen);
-    const activeSurface = useUIStore((state) => state.activeSurface);
     const setIsMobile = useUIStore((state) => state.setIsMobile);
     const isSettingsDialogOpen = useUIStore((state) => state.isSettingsDialogOpen);
     const setSettingsDialogOpen = useUIStore((state) => state.setSettingsDialogOpen);
@@ -71,12 +70,8 @@ export const MainLayout: React.FC = () => {
             const draftOpened = Boolean(state.newSessionDraft?.open) && state.newSessionDraft !== prev.newSessionDraft;
             if (sessionSelected || draftOpened) closeSurfacePages();
         });
-        const unsubscribeTab = useUIStore.subscribe((state, prev) => {
-            if (state.activeSurface !== prev.activeSurface) closeSurfacePages();
-        });
         return () => {
             unsubscribeSession();
-            unsubscribeTab();
         };
     }, []);
     const { isMobile } = useDeviceInfo();
@@ -90,8 +85,6 @@ export const MainLayout: React.FC = () => {
         }
     }, [isMobile, setIsMobile]);
 
-    const isChatActive = activeSurface === 'chat';
-
     return (
         <DiffWorkerProvider>
             <div
@@ -127,8 +120,8 @@ export const MainLayout: React.FC = () => {
                                         which the context panel animates. */}
                                     <div className="relative flex flex-1 min-h-0 min-w-0 overflow-hidden" data-page-scroll-lock="true" data-chat-area="true">
                                         <main className="flex-1 overflow-hidden bg-background relative" data-page-scroll-lock="true">
-                                            <div className={cn('absolute inset-0', (!isChatActive || isSurfacePageOpen) && 'invisible')}>
-                                                <ErrorBoundary><ChatView active={isChatActive && !isSettingsDialogOpen && !isSurfacePageOpen} /></ErrorBoundary>
+                                            <div className={cn('absolute inset-0', isSurfacePageOpen && 'invisible')}>
+                                                <ErrorBoundary><ChatView active={!isSettingsDialogOpen && !isSurfacePageOpen} /></ErrorBoundary>
                                             </div>
                                             {isMultiRunLauncherOpen && (
                                                 <div className="absolute inset-0 z-10 bg-background">
diff --git a/packages/ui/src/components/session/DirectoryExplorerDialog.tsx b/packages/ui/src/components/session/DirectoryExplorerDialog.tsx
index 1b7efbf8..e9e75314 100644
--- a/packages/ui/src/components/session/DirectoryExplorerDialog.tsx
+++ b/packages/ui/src/components/session/DirectoryExplorerDialog.tsx
@@ -148,7 +148,6 @@ export const DirectoryExplorerDialog: React.FC<DirectoryExplorerDialogProps> = (
   const homeDirectory = useDirectoryStore((s) => s.homeDirectory);
   const projects = useProjectsStore((s) => s.projects);
   const addProject = useProjectsStore((s) => s.addProject);
-  const setActiveSurface = useUIStore((s) => s.setActiveSurface);
   const setSessionSwitcherOpen = useUIStore((s) => s.setSessionSwitcherOpen);
   const openNewSessionDraft = useSessionUIStore((s) => s.openNewSessionDraft);
   const gitIdentityProfiles = useGitIdentitiesStore((s) => s.profiles);
@@ -411,11 +410,10 @@ export const DirectoryExplorerDialog: React.FC<DirectoryExplorerDialogProps> = (
   }, [onOpenChange]);
 
   const openProjectDraft = React.useCallback((projectId: string, projectPath: string) => {
-    setActiveSurface('chat');
     if (isMobile) setSessionSwitcherOpen(false);
     openNewSessionDraft({ selectedProjectId: projectId, directoryOverride: projectPath });
     handleClose();
-  }, [handleClose, isMobile, openNewSessionDraft, setActiveSurface, setSessionSwitcherOpen]);
+  }, [handleClose, isMobile, openNewSessionDraft, setSessionSwitcherOpen]);
 
   const handleQuickAdd = React.useCallback((event: React.MouseEvent, path: string) => {
     event.stopPropagation();
diff --git a/packages/ui/src/components/session/ScheduledTasksDialog.tsx b/packages/ui/src/components/session/ScheduledTasksDialog.tsx
index bc4b2f8b..299feec6 100644
--- a/packages/ui/src/components/session/ScheduledTasksDialog.tsx
+++ b/packages/ui/src/components/session/ScheduledTasksDialog.tsx
@@ -368,13 +368,9 @@ export function ScheduledTasksDialog() {
       return;
     }
     setOpen(false);
-    if (isMobile) {
-      useFilesViewTabsStore.getState().setSelectedPath(selectedProject.path, task.loopFile, { allowOutsideRoot: true });
-      useUIStore.getState().setActiveSurface('files');
-      return;
-    }
+    useFilesViewTabsStore.getState().setSelectedPath(selectedProject.path, task.loopFile, { allowOutsideRoot: true });
     useUIStore.getState().openContextFile(selectedProject.path, task.loopFile);
-  }, [isMobile, selectedProject?.path, setOpen]);
+  }, [selectedProject?.path, setOpen]);
 
   const handleRunNow = React.useCallback(async (task: ScheduledTask) => {
     if (!selectedProjectID) {
@@ -397,8 +393,7 @@ export function ScheduledTasksDialog() {
         // this surface (MainLayout closes surfaces on session selection).
         const project = projects.find((entry) => entry.id === selectedProjectID);
         useSessionUIStore.getState().setCurrentSession(sessionId, project?.path ?? null);
-        useUIStore.getState().setActiveSurface('chat');
-      }
+        }
     } catch (error) {
       toast.error(error instanceof Error ? error.message : t('sessions.scheduledTasks.dialog.toast.runFailed'));
     } finally {
diff --git a/packages/ui/src/components/session/SessionSidebar.tsx b/packages/ui/src/components/session/SessionSidebar.tsx
index 1ee1ca58..b59178da 100644
--- a/packages/ui/src/components/session/SessionSidebar.tsx
+++ b/packages/ui/src/components/session/SessionSidebar.tsx
@@ -391,7 +391,6 @@ const SessionSidebarComponent: React.FC<SessionSidebarProps> = ({
   const updateProjectMeta = useProjectsStore((state) => state.updateProjectMeta);
   const reorderProjects = useProjectsStore((state) => state.reorderProjects);
 
-  const setActiveSurface = useUIStore((state) => state.setActiveSurface);
   const openContextPanelTab = useUIStore((state) => state.openContextPanelTab);
   const setSettingsDialogOpen = useUIStore((state) => state.setSettingsDialogOpen);
   const toggleHelpDialog = useUIStore((state) => state.toggleHelpDialog);
@@ -848,7 +847,6 @@ const SessionSidebarComponent: React.FC<SessionSidebarProps> = ({
     sessionSearchQuery,
     setSessionSearchQuery,
     setIsSessionSearchOpen,
-    setActiveSurface,
     setSessionSwitcherOpen,
     setCurrentSession,
     updateSessionTitle,
@@ -1698,7 +1696,6 @@ const SessionSidebarComponent: React.FC<SessionSidebarProps> = ({
         alwaysShowActions={alwaysShowSidebarActions}
         activeProjectId={activeProjectId}
         setActiveProjectIdOnly={setActiveProjectIdOnly}
-        setActiveSurface={setActiveSurface}
         setSessionSwitcherOpen={setSessionSwitcherOpen}
         openNewSessionDraft={openNewSessionDraftFromTree}
         addSessionToFolder={addSessionToFolder}
@@ -1741,8 +1738,7 @@ const SessionSidebarComponent: React.FC<SessionSidebarProps> = ({
       alwaysShowSidebarActions,
       activeProjectId,
       setActiveProjectIdOnly,
-      setActiveSurface,
-      setSessionSwitcherOpen,
+        setSessionSwitcherOpen,
       openNewSessionDraftFromTree,
       addSessionToFolder,
       stableCreateFolderAndStartRename,
@@ -1763,12 +1759,11 @@ const SessionSidebarComponent: React.FC<SessionSidebarProps> = ({
 
   const handleOpenNewSessionDraftFromHeader = React.useCallback(() => {
     useUIStore.getState().closeMainSurfaces();
-    setActiveSurface('chat');
     if (mobileVariant) {
       setSessionSwitcherOpen(false);
     }
     openNewSessionDraft();
-  }, [mobileVariant, openNewSessionDraft, setActiveSurface, setSessionSwitcherOpen]);
+  }, [mobileVariant, openNewSessionDraft, setSessionSwitcherOpen]);
 
   const renderChatsSection = React.useCallback((items: ActivityItem[]) => {
     const chatsRoot = getChatsRootForHome(homeDirectory)
@@ -1850,12 +1845,11 @@ const SessionSidebarComponent: React.FC<SessionSidebarProps> = ({
     setBulkDeleteConfirm,
   });
   const handleOpenMultiRunFromHeader = React.useCallback(() => {
-    setActiveSurface('chat');
     if (mobileVariant) {
       setSessionSwitcherOpen(false);
     }
     openMultiRunLauncher();
-  }, [mobileVariant, openMultiRunLauncher, setActiveSurface, setSessionSwitcherOpen]);
+  }, [mobileVariant, openMultiRunLauncher, setSessionSwitcherOpen]);
 
   return (
     // One shared tooltip provider for the whole sidebar: session tooltips open
@@ -1889,7 +1883,6 @@ const SessionSidebarComponent: React.FC<SessionSidebarProps> = ({
         handleSessionSelect={stableHandleSessionSelect}
         mobileVariant={mobileVariant}
         openNewSessionDraft={openNewSessionDraft}
-        setActiveSurface={setActiveSurface}
         setSessionSwitcherOpen={setSessionSwitcherOpen}
         sessionOwnerBySessionId={sessionOwnership.bySessionId}
       />
@@ -1959,7 +1952,6 @@ const SessionSidebarComponent: React.FC<SessionSidebarProps> = ({
         alwaysShowActions={alwaysShowSidebarActions}
         toggleProject={toggleProject}
         setActiveProjectIdOnly={setActiveProjectIdOnly}
-        setActiveSurface={setActiveSurface}
         setSessionSwitcherOpen={setSessionSwitcherOpen}
         openNewSessionDraft={openNewSessionDraftFromTree}
         openNewWorktreeDialog={openNewWorktreeDialog}
@@ -2033,8 +2025,7 @@ const SessionSidebarComponent: React.FC<SessionSidebarProps> = ({
         open={newWorktreeDialogOpen}
         onOpenChange={setNewWorktreeDialogOpen}
         onWorktreeCreated={(worktreePath, options) => {
-          setActiveSurface('chat');
-          if (mobileVariant) {
+                if (mobileVariant) {
             setSessionSwitcherOpen(false);
           }
           if (options?.sessionId) {
diff --git a/packages/ui/src/components/session/SessionSwitcherDropdown.tsx b/packages/ui/src/components/session/SessionSwitcherDropdown.tsx
index 047fe8b6..f2adfc74 100644
--- a/packages/ui/src/components/session/SessionSwitcherDropdown.tsx
+++ b/packages/ui/src/components/session/SessionSwitcherDropdown.tsx
@@ -71,14 +71,12 @@ type SwitcherContentProps = {
 function SwitcherContent({ onSelect, variant, scopeProjectId }: SwitcherContentProps): React.ReactElement {
   const items = useSwitcherItems(true, { scopeProjectId });
   const openNewSessionDraft = useSessionUIStore((state) => state.openNewSessionDraft);
-  const setActiveSurface = useUIStore((state) => state.setActiveSurface);
   const { t } = useI18n();
 
   const handleNewSession = React.useCallback(() => {
-    setActiveSurface('chat');
     onSelect();
     openNewSessionDraft();
-  }, [onSelect, openNewSessionDraft, setActiveSurface]);
+  }, [onSelect, openNewSessionDraft]);
 
   const [expandedParents, setExpandedParents] = React.useState<Set<string>>(new Set());
   const toggleParent = React.useCallback((sessionId: string) => {
diff --git a/packages/ui/src/components/session/project-context/useProjectTodoSend.ts b/packages/ui/src/components/session/project-context/useProjectTodoSend.ts
index 8d6443ee..c85cf1ce 100644
--- a/packages/ui/src/components/session/project-context/useProjectTodoSend.ts
+++ b/packages/ui/src/components/session/project-context/useProjectTodoSend.ts
@@ -44,13 +44,11 @@ export const useProjectTodoSend = (options: {
   const sendMessage = useSessionUIStore((state) => state.sendMessage);
   const setCurrentSession = useSessionUIStore((state) => state.setCurrentSession);
   const setPendingInputText = useInputStore((state) => state.setPendingInputText);
-  const setActiveSurface = useUIStore((state) => state.setActiveSurface);
   const setSessionSwitcherOpen = useUIStore((state) => state.setSessionSwitcherOpen);
 
   const routeToChat = React.useCallback(() => {
-    setActiveSurface('chat');
     setSessionSwitcherOpen(false);
-  }, [setActiveSurface, setSessionSwitcherOpen]);
+  }, [setSessionSwitcherOpen]);
 
   const sendToCurrentSession = React.useCallback(
     (todoText: string) => {
diff --git a/packages/ui/src/components/session/sidebar/SessionGroupSection.tsx b/packages/ui/src/components/session/sidebar/SessionGroupSection.tsx
index ea1c3e1d..c80d3d73 100644
--- a/packages/ui/src/components/session/sidebar/SessionGroupSection.tsx
+++ b/packages/ui/src/components/session/sidebar/SessionGroupSection.tsx
@@ -14,7 +14,6 @@ import { Button } from '@/components/ui/button';
 import { Icon } from "@/components/icon/Icon";
 import { cn } from '@/lib/utils';
 import { sessionEvents } from '@/lib/sessionEvents';
-import type { WorkspaceSurface } from '@/stores/useUIStore';
 import { SessionFolderItem } from '../SessionFolderItem';
 import type { SortableDragHandleProps } from './sortableItems';
 import { DroppableFolderWrapper, SessionFolderDndScope } from './sessionFolderDnd';
@@ -84,7 +83,6 @@ type Props = {
   alwaysShowActions: boolean;
   activeProjectId: string | null;
   setActiveProjectIdOnly: (id: string) => void;
-  setActiveSurface: (tab: WorkspaceSurface) => void;
   setSessionSwitcherOpen: (open: boolean) => void;
   openNewSessionDraft: (options?: { selectedProjectId?: string | null; directoryOverride?: string | null; targetFolderId?: string; target?: 'chat' | 'project' }) => void;
   addSessionToFolder: (scopeKey: string, folderId: string, sessionId: string) => void;
@@ -265,7 +263,6 @@ const areGroupPropsEqual = (prev: Props, next: Props): boolean => {
     && prev.alwaysShowActions === next.alwaysShowActions
     && prev.activeProjectId === next.activeProjectId
     && prev.setActiveProjectIdOnly === next.setActiveProjectIdOnly
-    && prev.setActiveSurface === next.setActiveSurface
     && prev.setSessionSwitcherOpen === next.setSessionSwitcherOpen
     && prev.openNewSessionDraft === next.openNewSessionDraft
     && prev.addSessionToFolder === next.addSessionToFolder
@@ -307,7 +304,6 @@ function SessionGroupSectionBase(props: Props): React.ReactNode {
     alwaysShowActions,
     activeProjectId,
     setActiveProjectIdOnly,
-    setActiveSurface,
     setSessionSwitcherOpen,
     openNewSessionDraft,
     addSessionToFolder,
@@ -880,7 +876,6 @@ function SessionGroupSectionBase(props: Props): React.ReactNode {
             depth={0}
             onNewSession={() => {
               if (projectId && projectId !== activeProjectId) setActiveProjectIdOnly(projectId);
-              setActiveSurface('chat');
               if (mobileVariant) setSessionSwitcherOpen(false);
                openNewSessionDraft({
                  selectedProjectId: projectId,
@@ -1248,8 +1243,7 @@ function SessionGroupSectionBase(props: Props): React.ReactNode {
                   onClick={(event) => {
                     event.stopPropagation();
                     if (projectId && projectId !== activeProjectId) setActiveProjectIdOnly(projectId);
-                    setActiveSurface('chat');
-                    if (mobileVariant) setSessionSwitcherOpen(false);
+                          if (mobileVariant) setSessionSwitcherOpen(false);
                     openNewSessionDraft({ selectedProjectId: projectId, directoryOverride: group.directory });
                   }}
                   className="inline-flex h-6 w-6 items-center justify-center rounded-md text-muted-foreground hover:text-foreground hover:bg-interactive-hover/50 focus-visible:outline-none focus-visible:ring-2 focus-visible:ring-primary/50"
diff --git a/packages/ui/src/components/session/sidebar/SidebarProjectsList.tsx b/packages/ui/src/components/session/sidebar/SidebarProjectsList.tsx
index 0eeead0e..83dac8f6 100644
--- a/packages/ui/src/components/session/sidebar/SidebarProjectsList.tsx
+++ b/packages/ui/src/components/session/sidebar/SidebarProjectsList.tsx
@@ -16,7 +16,6 @@ import type { SortableDragHandleProps } from './sortableItems';
 import { ProjectHeaderIdentity, SortableGroupItem, SortableProjectItem } from './sortableItems';
 import { formatProjectLabel } from './utils';
 import { useI18n } from '@/lib/i18n';
-import type { WorkspaceSurface } from '@/stores/useUIStore';
 import type { ProjectSortOrder } from '@/stores/useSessionDisplayStore';
 import { streamPerfCount } from '@/stores/utils/streamDebug';
 import { Icon } from '@/components/icon/Icon';
@@ -91,7 +90,6 @@ type Props = {
   alwaysShowActions: boolean;
   toggleProject: (id: string) => void;
   setActiveProjectIdOnly: (id: string) => void;
-  setActiveSurface: (tab: WorkspaceSurface) => void;
   setSessionSwitcherOpen: (open: boolean) => void;
   openNewSessionDraft: (options?: { selectedProjectId?: string | null; directoryOverride?: string | null }) => void;
   openNewWorktreeDialog: () => void;
@@ -362,7 +360,6 @@ function SidebarProjectsListComponent(props: Props): React.ReactNode {
                   }}
                   onNewSession={() => {
                     if (projectKey !== props.activeProjectId) props.setActiveProjectIdOnly(projectKey);
-                    props.setActiveSurface('chat');
                     if (props.mobileVariant) props.setSessionSwitcherOpen(false);
                     props.openNewSessionDraft({
                       selectedProjectId: projectKey,
@@ -371,7 +368,6 @@ function SidebarProjectsListComponent(props: Props): React.ReactNode {
                   }}
                   onNewWorktreeSession={() => {
                     if (projectKey !== props.activeProjectId) props.setActiveProjectIdOnly(projectKey);
-                    props.setActiveSurface('chat');
                     props.openNewWorktreeDialog();
                   }}
                   onManageWorktrees={() => props.openWorktreesPage(projectKey)}
diff --git a/packages/ui/src/components/session/sidebar/hooks/useProjectSessionSelection.ts b/packages/ui/src/components/session/sidebar/hooks/useProjectSessionSelection.ts
index 9f532faa..72dfb797 100644
--- a/packages/ui/src/components/session/sidebar/hooks/useProjectSessionSelection.ts
+++ b/packages/ui/src/components/session/sidebar/hooks/useProjectSessionSelection.ts
@@ -2,7 +2,6 @@ import React from 'react';
 import type { Session } from '@opencode-ai/sdk/v2';
 import type { SessionGroup, SessionNode } from '../types';
 import { normalizePath } from '../utils';
-import type { WorkspaceSurface } from '@/stores/useUIStore';
 import { useUIStore } from '@/stores/useUIStore';
 import { useSessionUIStore } from '@/sync/session-ui-store';
 
@@ -22,7 +21,6 @@ type Args = {
   newSessionDraftOpen: boolean;
   mobileVariant: boolean;
   openNewSessionDraft: (options?: { selectedProjectId?: string | null; directoryOverride?: string | null }) => void;
-  setActiveSurface: (tab: WorkspaceSurface) => void;
   setSessionSwitcherOpen: (open: boolean) => void;
 };
 
@@ -101,7 +99,6 @@ export const useProjectSessionSelection = (args: Args): void => {
     newSessionDraftOpen,
     mobileVariant,
     openNewSessionDraft,
-    setActiveSurface,
     setSessionSwitcherOpen,
   } = args;
 
@@ -205,7 +202,6 @@ export const useProjectSessionSelection = (args: Args): void => {
     previousActiveProjectRef.current = activeProjectId;
 
     if (selection.kind === 'open-draft') {
-      setActiveSurface('chat');
       if (mobileVariant) {
         setSessionSwitcherOpen(false);
       }
@@ -232,7 +228,6 @@ export const useProjectSessionSelection = (args: Args): void => {
     openNewSessionDraft,
     projectSections,
     projectSessionMeta,
-    setActiveSurface,
     setSessionSwitcherOpen,
     setActiveSessionByProject,
   ]);
diff --git a/packages/ui/src/components/session/sidebar/hooks/useSessionActions.ts b/packages/ui/src/components/session/sidebar/hooks/useSessionActions.ts
index 47fcb647..83d86939 100644
--- a/packages/ui/src/components/session/sidebar/hooks/useSessionActions.ts
+++ b/packages/ui/src/components/session/sidebar/hooks/useSessionActions.ts
@@ -3,7 +3,6 @@ import type { Session } from '@opencode-ai/sdk/v2';
 import { toast } from '@/components/ui';
 import { copyTextToClipboard } from '@/lib/clipboard';
 import { useI18n } from '@/lib/i18n';
-import type { WorkspaceSurface } from '@/stores/useUIStore';
 import { useUIStore } from '@/stores/useUIStore';
 import { streamPerfMark } from '@/stores/utils/streamDebug';
 import { useSessionUIStore } from '@/sync/session-ui-store';
@@ -30,7 +29,6 @@ type Args = {
   sessionSearchQuery: string;
   setSessionSearchQuery: (value: string) => void;
   setIsSessionSearchOpen: (open: boolean) => void;
-  setActiveSurface: (tab: WorkspaceSurface) => void;
   setSessionSwitcherOpen: (open: boolean) => void;
   setCurrentSession: (sessionId: string | null, directoryHint?: string | null) => void;
   updateSessionTitle: (id: string, title: string) => Promise<void>;
@@ -79,7 +77,6 @@ export const useSessionActions = (args: Args) => {
       };
 
       if (args.mobileVariant) {
-        args.setActiveSurface('chat');
         args.setSessionSwitcherOpen(false);
       }
 
diff --git a/packages/ui/src/components/ui/CommandPalette.tsx b/packages/ui/src/components/ui/CommandPalette.tsx
index 7910faad..77a111e6 100644
--- a/packages/ui/src/components/ui/CommandPalette.tsx
+++ b/packages/ui/src/components/ui/CommandPalette.tsx
@@ -81,7 +81,6 @@ export const CommandPalette: React.FC = () => {
 
   const isCommandPaletteOpen = useUIStore((s) => s.isCommandPaletteOpen);
   const setCommandPaletteOpen = useUIStore((s) => s.setCommandPaletteOpen);
-  const setActiveSurface = useUIStore((s) => s.setActiveSurface);
   const setSettingsDialogOpen = useUIStore((s) => s.setSettingsDialogOpen);
   const setSettingsPage = useUIStore((s) => s.setSettingsPage);
   const setSessionSwitcherOpen = useUIStore((s) => s.setSessionSwitcherOpen);
@@ -170,7 +169,6 @@ export const CommandPalette: React.FC = () => {
         shortcutId: 'new_chat',
         searchText: t('commandPalette.item.newSession'),
         onSelect: run(() => {
-          setActiveSurface('chat');
           setSessionSwitcherOpen(false);
           openNewSessionDraft();
         }),
@@ -263,8 +261,7 @@ export const CommandPalette: React.FC = () => {
     t,
     run,
     isMobile,
-    setActiveSurface,
-    setSessionSwitcherOpen,
+        setSessionSwitcherOpen,
     openNewSessionDraft,
     toggleSidebar,
     openContextSurface,
diff --git a/packages/ui/src/components/views/ArchiveView.tsx b/packages/ui/src/components/views/ArchiveView.tsx
index 26bba4fd..01748476 100644
--- a/packages/ui/src/components/views/ArchiveView.tsx
+++ b/packages/ui/src/components/views/ArchiveView.tsx
@@ -28,7 +28,6 @@ export function ArchiveView(): React.ReactNode {
   const { t } = useI18n();
   const open = useUIStore((state) => state.isArchivePageOpen);
   const setOpen = useUIStore((state) => state.setArchivePageOpen);
-  const setActiveSurface = useUIStore((state) => state.setActiveSurface);
   const setCurrentSession = useSessionUIStore((state) => state.setCurrentSession);
   const unarchiveSession = useSessionUIStore((state) => state.unarchiveSession);
   const homeDirectory = useDirectoryStore((state) => state.homeDirectory);
@@ -86,9 +85,8 @@ export function ArchiveView(): React.ReactNode {
   const openSession = React.useCallback((session: Session) => {
     const directory = normalizePath(resolveGlobalSessionDirectory(session));
     setCurrentSession(session.id, directory ?? undefined);
-    setActiveSurface('chat');
     setOpen(false);
-  }, [setActiveSurface, setCurrentSession, setOpen]);
+  }, [setCurrentSession, setOpen]);
 
   const restoreSession = React.useCallback((session: Session) => {
     void unarchiveSession(session.id).then((success) => {
diff --git a/packages/ui/src/components/views/FilesView.tsx b/packages/ui/src/components/views/FilesView.tsx
index a00ce036..ecedf593 100644
--- a/packages/ui/src/components/views/FilesView.tsx
+++ b/packages/ui/src/components/views/FilesView.tsx
@@ -939,7 +939,6 @@ export const FilesView: React.FC<FilesViewProps> = ({ mode = 'full' }) => {
 
   const [confirmDiscardOpen, setConfirmDiscardOpen] = React.useState(false);
   const pendingSelectFileRef = React.useRef<FileNode | null>(null);
-  const pendingTabRef = React.useRef<import('@/stores/useUIStore').WorkspaceSurface | null>(null);
   const pendingClosePathRef = React.useRef<string | null>(null);
   const skipDirtyOnceRef = React.useRef(false);
   const copiedContentTimeoutRef = React.useRef<number | null>(null);
@@ -1029,7 +1028,6 @@ export const FilesView: React.FC<FilesViewProps> = ({ mode = 'full' }) => {
   const [isDragging, setIsDragging] = React.useState(false);
 
   // Session/config for sending comments
-  const setSurfaceGuard = useUIStore((state) => state.setSurfaceGuard);
   const pendingFileNavigation = useUIStore((state) => state.pendingFileNavigation);
   const setPendingFileNavigation = useUIStore((state) => state.setPendingFileNavigation);
   const pendingFileFocusPath = useUIStore((state) => state.pendingFileFocusPath);
@@ -1098,10 +1096,9 @@ export const FilesView: React.FC<FilesViewProps> = ({ mode = 'full' }) => {
   React.useEffect(() => {
     setLineSelection(null);
     reset();
-    setSurfaceGuard(null);
     setDraftContent('');
     setIsSaving(false);
-  }, [selectedFile?.path, reset, setSurfaceGuard]);
+  }, [selectedFile?.path, reset]);
 
   React.useEffect(() => {
     setCommentSelection(lineSelection);
@@ -1711,32 +1708,6 @@ export const FilesView: React.FC<FilesViewProps> = ({ mode = 'full' }) => {
     }
   }, [contentDetectedBinary, draftContent, fileContent, fileLoading, files, isDirty, loadedFileLineEnding, loadedFilePath, readFileStat, root, selectedFile, t]);
 
-  React.useEffect(() => {
-    if (!isDirty) {
-      setSurfaceGuard(null);
-      return;
-    }
-
-    const guard = (_nextTab: import('@/stores/useUIStore').WorkspaceSurface) => {
-      if (skipDirtyOnceRef.current) {
-        skipDirtyOnceRef.current = false;
-        return true;
-      }
-      setConfirmDiscardOpen(true);
-      pendingTabRef.current = _nextTab;
-      return false;
-    };
-
-    setSurfaceGuard(guard);
-
-    return () => {
-      const currentGuard = useUIStore.getState().surfaceGuard;
-      if (currentGuard === guard) {
-        setSurfaceGuard(null);
-      }
-    };
-  }, [isDirty, setSurfaceGuard]);
-
   React.useEffect(() => {
     if (autoSaveEnabled) {
       return;
@@ -2136,11 +2107,9 @@ export const FilesView: React.FC<FilesViewProps> = ({ mode = 'full' }) => {
 
   const discardAndContinue = React.useCallback(() => {
     const nextFile = pendingSelectFileRef.current;
-    const nextTab = pendingTabRef.current;
     const closePath = pendingClosePathRef.current;
 
     pendingSelectFileRef.current = null;
-    pendingTabRef.current = null;
     pendingClosePathRef.current = null;
 
     // Allow one guarded navigation (tab/file) without re-opening dialog.
@@ -2179,15 +2148,10 @@ export const FilesView: React.FC<FilesViewProps> = ({ mode = 'full' }) => {
       return;
     }
 
-    if (nextTab) {
-      setSurfaceGuard(null);
-      useUIStore.getState().setActiveSurface(nextTab);
-    }
-  }, [displayedContent, handleSelectFile, isMobile, removeOpenPath, root, selectedFile?.path, setSurfaceGuard, setSelectedPath]);
+  }, [displayedContent, handleSelectFile, isMobile, removeOpenPath, root, selectedFile?.path, setSelectedPath]);
 
   const saveAndContinue = React.useCallback(async () => {
     const nextFile = pendingSelectFileRef.current;
-    const nextTab = pendingTabRef.current;
     const closePath = pendingClosePathRef.current;
 
     const saved = await saveDraft();
@@ -2197,7 +2161,6 @@ export const FilesView: React.FC<FilesViewProps> = ({ mode = 'full' }) => {
     }
 
     pendingSelectFileRef.current = null;
-    pendingTabRef.current = null;
     pendingClosePathRef.current = null;
 
     // We'll proceed after saving; suppress guard reopening.
@@ -2233,11 +2196,7 @@ export const FilesView: React.FC<FilesViewProps> = ({ mode = 'full' }) => {
       return;
     }
 
-    if (nextTab) {
-      setSurfaceGuard(null);
-      useUIStore.getState().setActiveSurface(nextTab);
-    }
-  }, [handleSelectFile, isMobile, removeOpenPath, root, saveDraft, selectedFile?.path, setSurfaceGuard, setSelectedPath]);
+  }, [handleSelectFile, isMobile, removeOpenPath, root, saveDraft, selectedFile?.path, setSelectedPath]);
 
   const handleCloseFile = React.useCallback((path: string) => {
     const isActive = selectedFile?.path === path;
diff --git a/packages/ui/src/components/views/PlanView.tsx b/packages/ui/src/components/views/PlanView.tsx
index a1ca3111..24c07aaa 100644
--- a/packages/ui/src/components/views/PlanView.tsx
+++ b/packages/ui/src/components/views/PlanView.tsx
@@ -168,7 +168,6 @@ export const PlanView: React.FC<PlanViewProps> = ({ targetPath = null, projectPl
   const activeProjectId = useProjectsStore((state) => state.activeProjectId);
   const gitDirectories = useGitStore((state) => state.directories);
   const effectiveDirectory = useEffectiveDirectory() ?? '';
-  const setActiveSurface = useUIStore((state) => state.setActiveSurface);
   const setSessionSwitcherOpen = useUIStore((state) => state.setSessionSwitcherOpen);
   const runtimeApis = useRuntimeAPIs();
   const { isMobile } = useDeviceInfo();
@@ -579,10 +578,9 @@ export const PlanView: React.FC<PlanViewProps> = ({ targetPath = null, projectPl
   }, []);
 
   const routeToChat = React.useCallback(() => {
-    setActiveSurface('chat');
     setSessionSwitcherOpen(false);
     onNavigatedToChat?.();
-  }, [onNavigatedToChat, setActiveSurface, setSessionSwitcherOpen]);
+  }, [onNavigatedToChat, setSessionSwitcherOpen]);
 
   const handleConfirmPlanSend = React.useCallback(
     async (execution: TodoSendExecution) => {
diff --git a/packages/ui/src/components/views/TerminalView.tsx b/packages/ui/src/components/views/TerminalView.tsx
index 3f465531..21d45de0 100644
--- a/packages/ui/src/components/views/TerminalView.tsx
+++ b/packages/ui/src/components/views/TerminalView.tsx
@@ -148,9 +148,7 @@ export const TerminalView: React.FC<TerminalViewProps> = ({ visible }) => {
         terminalControllerRef.current?.focus();
     }, [useTouchTerminalInput]);
 
-    const activeSurface = useUIStore((state) => state.activeSurface);
-    const isTerminalActive = activeSurface === 'terminal';
-    const isTerminalVisible = visible ?? isTerminalActive;
+    const isTerminalVisible = visible ?? false;
     const [hasOpenedTerminalViewport, setHasOpenedTerminalViewport] = React.useState(isTerminalVisible);
 
     React.useEffect(() => {
diff --git a/packages/ui/src/components/views/git/ConflictDialog.tsx b/packages/ui/src/components/views/git/ConflictDialog.tsx
index 3df26e6a..8c3c3f6e 100644
--- a/packages/ui/src/components/views/git/ConflictDialog.tsx
+++ b/packages/ui/src/components/views/git/ConflictDialog.tsx
@@ -10,7 +10,6 @@ import { Button } from '@/components/ui/button';
 
 import { useSessionUIStore } from '@/sync/session-ui-store';
 import { useInputStore } from '@/sync/input-store';
-import { useUIStore } from '@/stores/useUIStore';
 import { toast } from '@/components/ui';
 import { Icon } from "@/components/icon/Icon";
 import { getConflictDetails, type MergeConflictDetails } from '@/lib/gitApi';
@@ -41,7 +40,6 @@ export const ConflictDialog: React.FC<ConflictDialogProps> = ({
   const currentSessionId = useSessionUIStore((state) => state.currentSessionId);
   const setPendingInputText = useInputStore((state) => state.setPendingInputText);
   const setPendingSyntheticParts = useInputStore((state) => state.setPendingSyntheticParts);
-  const setActiveSurface = useUIStore((state) => state.setActiveSurface);
 
   const [isLoading, setIsLoading] = React.useState(false);
   const [conflictDetails, setConflictDetails] = React.useState<MergeConflictDetails | null>(null);
@@ -137,7 +135,6 @@ export const ConflictDialog: React.FC<ConflictDialogProps> = ({
       { text: context.payloadText, synthetic: true },
     ]);
 
-    setActiveSurface('chat');
     onClearState?.();
     onOpenChange(false);
   };
@@ -159,7 +156,6 @@ export const ConflictDialog: React.FC<ConflictDialogProps> = ({
       ],
     });
     // Navigate to chat tab so user sees the new session
-    setActiveSurface('chat');
     onClearState?.();
     onOpenChange(false);
   };
diff --git a/packages/ui/src/components/views/git/IntegrateCommitsSection.tsx b/packages/ui/src/components/views/git/IntegrateCommitsSection.tsx
index 2d8db8ea..f98a48a4 100644
--- a/packages/ui/src/components/views/git/IntegrateCommitsSection.tsx
+++ b/packages/ui/src/components/views/git/IntegrateCommitsSection.tsx
@@ -18,7 +18,6 @@ import { toast } from '@/components/ui';
 import { Icon } from "@/components/icon/Icon";
 import { useSessionUIStore } from '@/sync/session-ui-store';
 import { useInputStore } from '@/sync/input-store';
-import { useUIStore } from '@/stores/useUIStore';
 import { rankByQuery } from '@/lib/search/fuzzySearch';
 import { getGitCommitSummaries } from '@/lib/gitApi';
 import { renderMagicPrompt } from '@/lib/magicPrompts';
@@ -65,7 +64,6 @@ export const IntegrateCommitsSection: React.FC<{
 }) => {
   const { t } = useI18n();
   const currentSessionId = useSessionUIStore((s) => s.currentSessionId);
-  const setActiveSurface = useUIStore((s) => s.setActiveSurface);
   const [branchDropdownOpen, setBranchDropdownOpen] = React.useState(false);
   const [branchSearch, setBranchSearch] = React.useState('');
   const searchInputRef = React.useRef<HTMLInputElement>(null);
@@ -235,8 +233,6 @@ export const IntegrateCommitsSection: React.FC<{
           { text: context.payloadText, synthetic: true },
         ],
       });
-      // Navigate to chat tab so user sees the new session
-      setActiveSurface('chat');
       return;
     }
 
@@ -251,8 +247,7 @@ export const IntegrateCommitsSection: React.FC<{
       { text: context.instructionsText, synthetic: true },
       { text: context.payloadText, synthetic: true },
     ]);
-    setActiveSurface('chat');
-  }, [currentSessionId, setActiveSurface, buildConflictContext, openNewSessionDraft, setPendingInputText, setPendingSyntheticParts, t]);
+  }, [currentSessionId, buildConflictContext, openNewSessionDraft, setPendingInputText, setPendingSyntheticParts, t]);
 
   const handleMove = React.useCallback(async () => {
     if (ui.kind !== 'ready') return;
diff --git a/packages/ui/src/components/views/git/PullRequestSection.tsx b/packages/ui/src/components/views/git/PullRequestSection.tsx
index cb0dad8f..1a767916 100644
--- a/packages/ui/src/components/views/git/PullRequestSection.tsx
+++ b/packages/ui/src/components/views/git/PullRequestSection.tsx
@@ -327,7 +327,6 @@ export const PullRequestSection: React.FC<{
   const githubAuthChecked = useGitHubAuthStore((state) => state.hasChecked);
   const setSettingsDialogOpen = useUIStore((state) => state.setSettingsDialogOpen);
   const setSettingsPage = useUIStore((state) => state.setSettingsPage);
-  const setActiveSurface = useUIStore((state) => state.setActiveSurface);
   const currentSessionId = useSessionUIStore((state) => state.currentSessionId);
   const newSessionDraftOpen = useSessionUIStore((state) => Boolean(state.newSessionDraft?.open));
   const { isMobile, hasTouchInput, screenWidth } = useDeviceInfo();
@@ -986,14 +985,13 @@ export const PullRequestSection: React.FC<{
           text: '',
         });
       }
-      setActiveSurface('chat');
     } catch (e) {
       const message = e instanceof Error ? e.message : String(e);
       toast.error(t('gitView.pr.toast.loadChecksFailed'), { description: message });
     } finally {
       setIsAttachingChecks(false);
     }
-  }, [directory, ensurePrContext, github, pr, resolveDraftTarget, setActiveSurface, status?.repo, t]);
+  }, [directory, ensurePrContext, github, pr, resolveDraftTarget, status?.repo, t]);
 
   const sendCommentsToChat = React.useCallback(async () => {
     if (!github?.prContext) {
@@ -1021,14 +1019,13 @@ export const PullRequestSection: React.FC<{
       for (const comment of timelineComments) {
         attachCommentDraft(target, comment);
       }
-      setActiveSurface('chat');
     } catch (e) {
       const message = e instanceof Error ? e.message : String(e);
       toast.error(t('gitView.pr.toast.loadPrCommentsFailed'), { description: message });
     } finally {
       setIsAttachingComments(false);
     }
-  }, [attachCommentDraft, directory, ensurePrContext, github, pr, resolveDraftTarget, setActiveSurface, status?.repo, t, timelineComments]);
+  }, [attachCommentDraft, directory, ensurePrContext, github, pr, resolveDraftTarget, status?.repo, t, timelineComments]);
 
   const sendSingleCommentToChat = React.useCallback(async (comment: TimelineCommentItem) => {
     const target = resolveDraftTarget();
@@ -1037,8 +1034,7 @@ export const PullRequestSection: React.FC<{
     }
 
     attachCommentDraft(target, comment);
-    setActiveSurface('chat');
-  }, [attachCommentDraft, resolveDraftTarget, setActiveSurface]);
+  }, [attachCommentDraft, resolveDraftTarget]);
 
   const refresh = React.useCallback(async (options?: { force?: boolean; onlyExistingPr?: boolean; silent?: boolean; markInitialResolved?: boolean }) => {
     await refreshPrStatus(prStatusKey, options);
diff --git a/packages/ui/src/hooks/useKeyboardShortcuts.ts b/packages/ui/src/hooks/useKeyboardShortcuts.ts
index f66b66ff..2d2c4439 100644
--- a/packages/ui/src/hooks/useKeyboardShortcuts.ts
+++ b/packages/ui/src/hooks/useKeyboardShortcuts.ts
@@ -59,7 +59,6 @@ export const useKeyboardShortcuts = () => {
   }, [currentShortcutDirectory]);
   const isMobile = useUIStore((s) => s.isMobile);
   const setSessionSwitcherOpen = useUIStore((s) => s.setSessionSwitcherOpen);
-  const setActiveSurface = useUIStore((s) => s.setActiveSurface);
   const setSettingsDialogOpen = useUIStore((s) => s.setSettingsDialogOpen);
   const setModelSelectorOpen = useUIStore((s) => s.setModelSelectorOpen);
   const setTimelineDialogOpen = useUIStore((s) => s.setTimelineDialogOpen);
@@ -154,7 +153,6 @@ export const useKeyboardShortcuts = () => {
         isAboutDialogOpen,
         isMultiRunLauncherOpen,
         isImagePreviewOpen,
-        activeSurface,
         isPromptNavigatorPanelOpen,
       } = useUIStore.getState();
 
@@ -183,7 +181,7 @@ export const useKeyboardShortcuts = () => {
       }
 
       const hasOverlay = isCommandPaletteOpen || isHelpDialogOpen || isSessionSwitcherOpen || isAboutDialogOpen || isMultiRunLauncherOpen || isImagePreviewOpen;
-      const isChatActive = activeSurface === 'chat';
+      const isChatActive = true;
 
       if (hasOverlay || !isChatActive) {
         resetAbortPriming();
@@ -245,7 +243,6 @@ export const useKeyboardShortcuts = () => {
 
       if (eventMatchesShortcut(e, combo('toggle_prompt_navigator'))) {
         const {
-          activeSurface,
           promptNavigatorEnabled,
           isSettingsDialogOpen,
           isCommandPaletteOpen,
@@ -257,7 +254,7 @@ export const useKeyboardShortcuts = () => {
           isImagePreviewOpen,
         } = useUIStore.getState();
 
-        if (!promptNavigatorEnabled || isMobile || isVSCodeRuntime() || activeSurface !== 'chat') {
+        if (!promptNavigatorEnabled || isMobile || isVSCodeRuntime()) {
           return;
         }
 
@@ -308,7 +305,6 @@ export const useKeyboardShortcuts = () => {
       if (matchedNewSessionShortcut || matchedWorktreeShortcut) {
         e.preventDefault();
 
-        setActiveSurface('chat');
         setSessionSwitcherOpen(false);
 
         if (!isVSCodeRuntime() && matchedWorktreeShortcut) {
@@ -394,11 +390,10 @@ export const useKeyboardShortcuts = () => {
           isHelpDialogOpen,
           isSessionSwitcherOpen,
           isAboutDialogOpen,
-          activeSurface,
         } = useUIStore.getState();
 
         const hasOverlay = isSettingsDialogOpen || isCommandPaletteOpen || isHelpDialogOpen || isSessionSwitcherOpen || isAboutDialogOpen;
-        if (hasOverlay || activeSurface !== 'chat' || !isChatInputTarget(e.target)) {
+        if (hasOverlay || !isChatInputTarget(e.target)) {
           return;
         }
 
@@ -525,7 +520,6 @@ export const useKeyboardShortcuts = () => {
           isHelpDialogOpen,
           isSessionSwitcherOpen,
           isAboutDialogOpen,
-          activeSurface,
           isModelSelectorOpen,
         } = useUIStore.getState();
 
@@ -536,7 +530,7 @@ export const useKeyboardShortcuts = () => {
 
         // Skip if any overlay open or not on chat tab
         const hasOverlay = isCommandPaletteOpen || isHelpDialogOpen || isSessionSwitcherOpen || isAboutDialogOpen;
-        const isChatActive = activeSurface === 'chat';
+        const isChatActive = true;
 
         if (hasOverlay || !isChatActive) {
           return;
@@ -555,7 +549,6 @@ export const useKeyboardShortcuts = () => {
           isHelpDialogOpen,
           isSessionSwitcherOpen,
           isAboutDialogOpen,
-          activeSurface,
         } = useUIStore.getState();
 
         if (isSettingsDialogOpen) {
@@ -563,7 +556,7 @@ export const useKeyboardShortcuts = () => {
         }
 
         const hasOverlay = isCommandPaletteOpen || isHelpDialogOpen || isSessionSwitcherOpen || isAboutDialogOpen;
-        const isChatActive = activeSurface === 'chat';
+        const isChatActive = true;
 
         if (hasOverlay || !isChatActive) {
           return;
@@ -602,7 +595,6 @@ export const useKeyboardShortcuts = () => {
           isHelpDialogOpen,
           isSessionSwitcherOpen,
           isAboutDialogOpen,
-          activeSurface,
           favoriteModels,
           addRecentModel,
         } = useUIStore.getState();
@@ -612,7 +604,7 @@ export const useKeyboardShortcuts = () => {
         }
 
         const hasOverlay = isCommandPaletteOpen || isHelpDialogOpen || isSessionSwitcherOpen || isAboutDialogOpen;
-        const isChatActive = activeSurface === 'chat';
+        const isChatActive = true;
 
         if (hasOverlay || !isChatActive || favoriteModels.length === 0) {
           return;
@@ -644,8 +636,8 @@ export const useKeyboardShortcuts = () => {
       }
 
       if (eventMatchesShortcut(e, combo('toggle_dictation'))) {
-        const { activeSurface, isCommandPaletteOpen, isHelpDialogOpen, isSessionSwitcherOpen, isSettingsDialogOpen } = useUIStore.getState();
-        if (activeSurface !== 'chat' || isCommandPaletteOpen || isHelpDialogOpen || isSessionSwitcherOpen || isSettingsDialogOpen) {
+        const { isCommandPaletteOpen, isHelpDialogOpen, isSessionSwitcherOpen, isSettingsDialogOpen } = useUIStore.getState();
+        if (isCommandPaletteOpen || isHelpDialogOpen || isSessionSwitcherOpen || isSettingsDialogOpen) {
           return;
         }
         e.preventDefault();
@@ -695,7 +687,6 @@ export const useKeyboardShortcuts = () => {
     toggleTerminalSurfaceExpanded,
     isMobile,
     setSessionSwitcherOpen,
-    setActiveSurface,
     setSettingsDialogOpen,
     setModelSelectorOpen,
     setTimelineDialogOpen,
diff --git a/packages/ui/src/hooks/useMenuActions.ts b/packages/ui/src/hooks/useMenuActions.ts
index 03f16abf..dd163593 100644
--- a/packages/ui/src/hooks/useMenuActions.ts
+++ b/packages/ui/src/hooks/useMenuActions.ts
@@ -102,7 +102,6 @@ export const useMenuActions = (
   const toggleHelpDialog = useUIStore((s) => s.toggleHelpDialog);
   const toggleSidebar = useUIStore((s) => s.toggleSidebar);
   const setSessionSwitcherOpen = useUIStore((s) => s.setSessionSwitcherOpen);
-  const setActiveSurface = useUIStore((s) => s.setActiveSurface);
   const setSettingsDialogOpen = useUIStore((s) => s.setSettingsDialogOpen);
   const setAboutDialogOpen = useUIStore((s) => s.setAboutDialogOpen);
   const checkForUpdates = useUpdateStore((state) => state.checkForUpdates);
@@ -151,10 +150,9 @@ export const useMenuActions = (
     const nextSession = sessions[nextIndex];
     if (!nextSession) return;
 
-    setActiveSurface('chat');
     setSessionSwitcherOpen(false);
     useSessionUIStore.getState().setCurrentSession(nextSession.id);
-  }, [setActiveSurface, setSessionSwitcherOpen]);
+  }, [setSessionSwitcherOpen]);
 
   const navigateProject = React.useCallback((direction: -1 | 1) => {
     const { activeProjectId, projects, setActiveProject } = useProjectsStore.getState();
@@ -191,8 +189,7 @@ export const useMenuActions = (
           break;
 
         case 'new-session':
-          setActiveSurface('chat');
-          setSessionSwitcherOpen(false);
+                setSessionSwitcherOpen(false);
           {
             const sessionState = useSessionUIStore.getState();
             const directory = useDirectoryStore.getState().currentDirectory;
@@ -203,8 +200,7 @@ export const useMenuActions = (
           break;
 
         case 'new-worktree-session':
-          setActiveSurface('chat');
-          setSessionSwitcherOpen(false);
+                setSessionSwitcherOpen(false);
           createWorktreeSession();
           break;
 
@@ -341,7 +337,6 @@ export const useMenuActions = (
       onToggleMemoryDebug,
       openNewSessionDraft,
       setAboutDialogOpen,
-      setActiveSurface,
       setSessionSwitcherOpen,
       setCommandPaletteOpen,
       setSettingsDialogOpen,
diff --git a/packages/ui/src/hooks/useRouter.ts b/packages/ui/src/hooks/useRouter.ts
index a1d3d5ca..2379f9be 100644
--- a/packages/ui/src/hooks/useRouter.ts
+++ b/packages/ui/src/hooks/useRouter.ts
@@ -3,7 +3,6 @@ import { useSessionUIStore } from '@/sync/session-ui-store';
 import { useUIStore, type ContextPanelMode } from '@/stores/useUIStore';
 import { parseRoute, updateBrowserURL, hasRouteParams } from '@/lib/router';
 import type { RouteState, AppRouteState } from '@/lib/router';
-import type { WorkspaceSurface } from '@/stores/useUIStore';
 import { resolveSettingsSlug } from '@/lib/settings/metadata';
 import { isEmbeddedSessionChat } from '@/components/layout/contextPanelEmbeddedChat';
 import { useDirectoryStore } from '@/stores/useDirectoryStore';
@@ -50,7 +49,6 @@ export function useRouter(): void {
 
   // Get store actions (stable references)
   const setCurrentSession = useSessionUIStore((state) => state.setCurrentSession);
-  const setActiveSurface = useUIStore((state) => state.setActiveSurface);
   const setSettingsDialogOpen = useUIStore((state) => state.setSettingsDialogOpen);
   const setSettingsPage = useUIStore((state) => state.setSettingsPage);
   const navigateToDiff = useUIStore((state) => state.navigateToDiff);
@@ -109,7 +107,7 @@ export function useRouter(): void {
         isApplyingRouteRef.current = false;
       }
     },
-    [setCurrentSession, setActiveSurface, setSettingsDialogOpen, setSettingsPage, navigateToDiff]
+    [setCurrentSession, setSettingsDialogOpen, setSettingsPage, navigateToDiff]
   );
 
   /**
@@ -121,10 +119,8 @@ export function useRouter(): void {
 
     return {
       sessionId: sessionState.currentSessionId,
-      tab: uiState.activeSurface,
       isSettingsOpen: uiState.isSettingsDialogOpen,
       settingsPath: uiState.settingsPage,
-      diffFile: uiState.pendingDiffFile,
     };
   }, []);
 
@@ -170,9 +166,7 @@ export function useRouter(): void {
         updateBrowserURL({
           ...getCurrentAppState(),
           sessionId: route.sessionId ?? useSessionUIStore.getState().currentSessionId,
-          tab: route.tab ?? useUIStore.getState().activeSurface,
           settingsPath: route.settingsPath ?? useUIStore.getState().settingsPage,
-          diffFile: route.diffFile ?? useUIStore.getState().pendingDiffFile,
         }, { replace: true, force: true });
       }
     };
@@ -209,10 +203,8 @@ export function useRouter(): void {
       return;
     }
 
-    let prevSurface: WorkspaceSurface = useUIStore.getState().activeSurface;
     let prevSettingsOpen: boolean = useUIStore.getState().isSettingsDialogOpen;
     let prevSettingsPath: string = useUIStore.getState().settingsPage;
-    let prevDiffFile: string | null = useUIStore.getState().pendingDiffFile;
 
     const unsubscribe = useUIStore.subscribe((state) => {
       // Skip if we're currently applying a route
@@ -220,19 +212,13 @@ export function useRouter(): void {
         return;
       }
 
-      const surfaceChanged = state.activeSurface !== prevSurface;
       const settingsOpenChanged = state.isSettingsDialogOpen !== prevSettingsOpen;
       const settingsPathChanged = state.settingsPage !== prevSettingsPath;
-      const diffFileChanged = state.pendingDiffFile !== prevDiffFile && state.activeSurface === 'diff';
 
-      // Update tracking vars
-      prevSurface = state.activeSurface;
       prevSettingsOpen = state.isSettingsDialogOpen;
       prevSettingsPath = state.settingsPage;
-      prevDiffFile = state.pendingDiffFile;
 
-      // Only sync if something relevant changed
-      if (surfaceChanged || settingsOpenChanged || settingsPathChanged || diffFileChanged) {
+      if (settingsOpenChanged || settingsPathChanged) {
         syncURLFromState();
       }
     });
@@ -260,10 +246,6 @@ export function useRouter(): void {
         if (uiState.isSettingsDialogOpen) {
           setSettingsDialogOpen(false);
         }
-        // Reset to chat when no route view is specified.
-        if (uiState.activeSurface !== 'chat') {
-          setActiveSurface('chat');
-        }
       }
     };
 
@@ -272,5 +254,5 @@ export function useRouter(): void {
     return () => {
       window.removeEventListener('popstate', handlePopState);
     };
-  }, [applyRoute, isVSCode, isEmbeddedChat, setActiveSurface, setSettingsDialogOpen]);
+  }, [applyRoute, isVSCode, isEmbeddedChat, setSettingsDialogOpen]);
 }
diff --git a/packages/ui/src/lib/addSelectionToChat.ts b/packages/ui/src/lib/addSelectionToChat.ts
index a35e892b..fe1d8912 100644
--- a/packages/ui/src/lib/addSelectionToChat.ts
+++ b/packages/ui/src/lib/addSelectionToChat.ts
@@ -151,7 +151,6 @@ export const captureSelectionMarkdownForChat = (): string | null => {
 export const addSelectionToChat = (): boolean => {
   const markdown = captureSelectionMarkdownForChat();
 
-  useUIStore.getState().setActiveSurface('chat');
   useUIStore.getState().setSessionSwitcherOpen(false);
 
   if (markdown) {
diff --git a/packages/ui/src/lib/router/parseRoute.ts b/packages/ui/src/lib/router/parseRoute.ts
index 458fb4f9..757ccfb6 100644
--- a/packages/ui/src/lib/router/parseRoute.ts
+++ b/packages/ui/src/lib/router/parseRoute.ts
@@ -1,6 +1,6 @@
-import type { WorkspaceSurface } from '@/stores/useUIStore';
 import {
   type RouteState,
+  type RouteTab,
   VALID_TABS,
   VALID_SETTINGS_SECTIONS,
   ROUTE_PARAMS,
@@ -52,13 +52,13 @@ function parseSessionId(params: URLSearchParams): string | null {
  * Parse main tab from URL parameters.
  * Returns null if missing or invalid.
  */
-function parseTab(params: URLSearchParams): WorkspaceSurface | null {
+function parseTab(params: URLSearchParams): RouteTab | null {
   const value = params.get(ROUTE_PARAMS.TAB);
   if (!value) {
     return null;
   }
 
-  const normalized = value.toLowerCase().trim() as WorkspaceSurface;
+  const normalized = value.toLowerCase().trim() as RouteTab;
   if (VALID_TABS.includes(normalized)) {
     return normalized;
   }
diff --git a/packages/ui/src/lib/router/serializeRoute.test.ts b/packages/ui/src/lib/router/serializeRoute.test.ts
index bfb98ff6..f0d458c8 100644
--- a/packages/ui/src/lib/router/serializeRoute.test.ts
+++ b/packages/ui/src/lib/router/serializeRoute.test.ts
@@ -65,10 +65,8 @@ afterAll(() => {
 
 const sessionState = (sessionId: string): AppRouteState => ({
   sessionId,
-  tab: 'chat',
   isSettingsOpen: false,
   settingsPath: '',
-  diffFile: null,
 });
 
 describe('updateBrowserURL embedded-session-chat guard', () => {
diff --git a/packages/ui/src/lib/router/serializeRoute.ts b/packages/ui/src/lib/router/serializeRoute.ts
index 6b6e054c..75307af2 100644
--- a/packages/ui/src/lib/router/serializeRoute.ts
+++ b/packages/ui/src/lib/router/serializeRoute.ts
@@ -1,4 +1,3 @@
-import type { WorkspaceSurface } from '@/stores/useUIStore';
 import { isEmbeddedSessionChat } from '@/components/layout/contextPanelEmbeddedChat';
 import { ROUTE_PARAMS } from './types';
 
@@ -7,17 +6,10 @@ import { ROUTE_PARAMS } from './types';
  */
 export interface AppRouteState {
   sessionId: string | null;
-  tab: WorkspaceSurface;
   isSettingsOpen: boolean;
   settingsPath: string;
-  diffFile: string | null;
 }
 
-/**
- * Default tab when none is specified.
- */
-const DEFAULT_TAB: WorkspaceSurface = 'chat';
-
 /**
  * Serialize application state to URL search parameters.
  * Only includes parameters that differ from defaults to keep URLs clean.
@@ -38,15 +30,6 @@ function serializeRoute(state: AppRouteState): URLSearchParams {
     return params;
   }
 
-  // Tab - only include if not the default
-  if (state.tab !== DEFAULT_TAB) {
-    params.set(ROUTE_PARAMS.TAB, state.tab);
-  }
-
-  // Diff file - only include when on diff tab
-  if (state.tab === 'diff' && state.diffFile && state.diffFile.trim().length > 0) {
-    params.set(ROUTE_PARAMS.FILE, state.diffFile);
-  }
 
   return params;
 }
diff --git a/packages/ui/src/lib/router/types.ts b/packages/ui/src/lib/router/types.ts
index 25c838a6..d4dcf61a 100644
--- a/packages/ui/src/lib/router/types.ts
+++ b/packages/ui/src/lib/router/types.ts
@@ -1,5 +1,4 @@
 import type { SidebarSection } from '@/constants/sidebar';
-import type { WorkspaceSurface } from '@/stores/useUIStore';
 
 /**
  * Represents the current route state derived from URL parameters.
@@ -9,7 +8,7 @@ export interface RouteState {
   /** Session ID to navigate to */
   sessionId: string | null;
   /** View selected through the legacy `tab` URL parameter. */
-  tab: WorkspaceSurface | null;
+  tab: RouteTab | null;
   /** Settings section - when non-null, settings dialog should be open */
   settingsPath: string | null;
   /** File path for diff view */
@@ -17,9 +16,11 @@ export interface RouteState {
 }
 
 /**
- * Valid values for the legacy `tab` URL parameter.
+ * Valid values for the legacy `tab` URL parameter. Non-chat tabs open the
+ * matching context-panel surface; the chat always owns the main area.
  */
-export const VALID_TABS: readonly WorkspaceSurface[] = ['chat', 'git', 'diff', 'terminal', 'files'] as const;
+export type RouteTab = 'chat' | 'git' | 'diff' | 'terminal' | 'files';
+export const VALID_TABS: readonly RouteTab[] = ['chat', 'git', 'diff', 'terminal', 'files'] as const;
 
 /**
  * Valid settings section values for URL routing.
diff --git a/packages/ui/src/stores/useUIStore.ts b/packages/ui/src/stores/useUIStore.ts
index 2a1ca610..bbbe08b4 100644
--- a/packages/ui/src/stores/useUIStore.ts
+++ b/packages/ui/src/stores/useUIStore.ts
@@ -7,17 +7,11 @@ import type { ShortcutCombo } from '@/lib/shortcuts';
 import type { DraftStarterRef } from '@/lib/draftStarters';
 import { DEFAULT_MONO_FONT, DEFAULT_UI_FONT, type MonoFontOption, type UiFontOption } from '@/lib/fontOptions';
 import { getStoredMobileKeyboardMode, type MobileKeyboardMode } from '@/lib/mobileKeyboardMode';
-import { getRuntimeKey } from '@/lib/runtime-switch';
 import type { TerminalShell } from '@/lib/api/types';
 import { useFilesViewTabsStore } from './useFilesViewTabsStore';
 import { isWindowsArm64 } from '@/lib/platform';
 import { isVSCodeRuntime } from '@/lib/desktop';
 
-/**
- * The primary view on mobile and the desktop's promoted full-screen view.
- * Desktop context-panel content is not represented here.
- */
-export type WorkspaceSurface = 'chat' | 'plan' | 'git' | 'diff' | 'terminal' | 'files' | 'context';
 export type PendingDiffScope = 'working' | 'staged' | 'turn' | 'branch';
 export type ContextPanelMode = 'diff' | 'walkthrough' | 'file' | 'context' | 'plan' | 'chat' | 'browser' | 'git' | 'pr' | 'notes' | 'terminal';
 export type MermaidRenderingMode = 'svg' | 'ascii';
@@ -81,7 +75,6 @@ type PendingFileNavigation = {
   column: number;
 };
 
-export type WorkspaceSurfaceGuard = (nextSurface: WorkspaceSurface) => boolean;
 export type EventStreamStatus =
   | 'idle'
   | 'connecting'
@@ -133,15 +126,9 @@ const CONTEXT_PANEL_MAX_WIDTH = 1400;
 const CONTEXT_PANEL_MAX_TABS = 12;
 const CONTEXT_PANEL_MAX_LABEL_LENGTH = 120;
 const LEFT_SIDEBAR_MIN_WIDTH = 280;
-const activeSurfaceByRuntime = new Map<string, WorkspaceSurface>();
 /** Separates browser tabs opened in the same millisecond. */
 let browserTabSequence = 0;
 
-const runtimeMemoryKey = (value?: string | null): string => {
-  const key = (value ?? getRuntimeKey()).trim();
-  return key || 'default';
-};
-
 // Shared with rail/panel consumers so contextPanelByDirectory lookups agree on keys.
 export const normalizeContextPanelDirectoryKey = (value: string): string => normalizeDirectoryPath(value);
 
@@ -652,9 +639,6 @@ interface UIStore {
   workStatusHiddenSections: string[];
   isSessionSwitcherOpen: boolean;
   isSessionDropdownOpen: boolean;
-  activeSurface: WorkspaceSurface;
-  surfaceGuard: WorkspaceSurfaceGuard | null;
-  sidebarOpenBeforeFullscreenTab: boolean | null;
   pendingDiffFile: string | null;
   pendingDiffStaged: boolean;
   pendingDiffScope: PendingDiffScope | null;
@@ -844,10 +828,6 @@ interface UIStore {
   setWorkStatusHiddenSections: (sectionIds: string[]) => void;
   setSessionSwitcherOpen: (open: boolean) => void;
   setSessionDropdownOpen: (open: boolean) => void;
-  setActiveSurface: (surface: WorkspaceSurface) => void;
-  prepareForRuntimeSwitch: (runtimeKey?: string | null) => void;
-  restoreForRuntimeSwitch: (runtimeKey?: string | null) => void;
-  setSurfaceGuard: (guard: WorkspaceSurfaceGuard | null) => void;
   setPendingDiffFile: (filePath: string | null, staged?: boolean, scope?: PendingDiffScope | null) => void;
   setPendingFileNavigation: (navigation: PendingFileNavigation | null) => void;
   setPendingFileFocusPath: (path: string | null) => void;
@@ -1019,9 +999,6 @@ export const useUIStore = create<UIStore>()(
         workStatusHiddenSections: [],
         isSessionSwitcherOpen: false,
         isSessionDropdownOpen: false,
-        activeSurface: 'chat',
-        surfaceGuard: null,
-        sidebarOpenBeforeFullscreenTab: null,
         pendingDiffFile: null,
         pendingDiffStaged: false,
         pendingDiffScope: null,
@@ -1633,31 +1610,6 @@ export const useUIStore = create<UIStore>()(
           set({ isSessionDropdownOpen: open });
         },
 
-        setSurfaceGuard: (guard) => {
-          if (get().surfaceGuard === guard) {
-            return;
-          }
-          set({ surfaceGuard: guard });
-        },
-
-        setActiveSurface: (surface) => {
-          const guard = get().surfaceGuard;
-          if (guard && !guard(surface)) {
-            return;
-          }
-          activeSurfaceByRuntime.set(runtimeMemoryKey(), surface);
-          set({ activeSurface: surface });
-        },
-
-        prepareForRuntimeSwitch: (runtimeKey?: string | null) => {
-          activeSurfaceByRuntime.set(runtimeMemoryKey(runtimeKey), get().activeSurface);
-        },
-
-        restoreForRuntimeSwitch: (runtimeKey?: string | null) => {
-          const restored = activeSurfaceByRuntime.get(runtimeMemoryKey(runtimeKey)) ?? 'chat';
-          set({ activeSurface: restored });
-        },
-
         setPendingDiffFile: (filePath, staged = false, scope = null) => {
           set({
             pendingDiffFile: filePath,
@@ -1675,11 +1627,7 @@ export const useUIStore = create<UIStore>()(
         },
 
         navigateToDiff: (filePath, staged = false, scope = null) => {
-          const guard = get().surfaceGuard;
-          if (guard && !guard('diff')) {
-            return;
-          }
-          set({ pendingDiffFile: filePath, pendingDiffStaged: staged, pendingDiffScope: scope, activeSurface: 'diff' });
+          set({ pendingDiffFile: filePath, pendingDiffStaged: staged, pendingDiffScope: scope });
         },
 
         consumePendingDiffFile: () => {