Reduce workspace render churn

packages/app/src/components/left-sidebar.tsx

@@ -41,7 +41,10 @@ import { Shortcut } from "@/components/ui/shortcut";
 import { Tooltip, TooltipContent, TooltipTrigger } from "@/components/ui/tooltip";
 import { useIsCompactFormFactor } from "@/constants/layout";
 import { isWeb } from "@/constants/platform";
-import { useSidebarAnimation } from "@/contexts/sidebar-animation-context";
+import {
+  useSidebarAnimation,
+  useSidebarSettledGeneration,
+} from "@/contexts/sidebar-animation-context";
 import { useOpenProjectPicker } from "@/hooks/use-open-project-picker";
 import { useShortcutKeys } from "@/hooks/use-shortcut-keys";
 import { useSidebarShortcutModel } from "@/hooks/use-sidebar-shortcut-model";
@@ -615,12 +618,12 @@ function MobileSidebar({
     windowWidth,
     animateToOpen,
     animateToClose,
-    settledGeneration,
     isGesturing,
     mobilePanelState,
     gestureAnimatingRef,
     closeGestureRef,
   } = useSidebarAnimation();
+  const settledGeneration = useSidebarSettledGeneration();
   const closeTouchStartX = useSharedValue(0);
   const closeTouchStartY = useSharedValue(0);
 

packages/app/src/components/split-container.tsx

@@ -1,5 +1,6 @@
 import {
   Fragment,
+  createContext,
   memo,
   useCallback,
   useEffect,
@@ -73,6 +74,10 @@ import { RenderProfile } from "@/utils/render-profiler";
 import { workspaceTabTargetsEqual } from "@/workspace-tabs/identity";
 import { isNative } from "@/constants/platform";
 
+// true = this tab slot is the active (visible) tab; false = mounted but hidden.
+// Defaults to true so consumers outside a slot (e.g. web preview) are unaffected.
+export const MountedTabActiveContext = createContext<boolean>(true);
+
 interface SplitContainerProps {
   layout: WorkspaceLayout;
   workspaceKey: string;
@@ -219,14 +224,16 @@ const MountedTabSlot = memo(function MountedTabSlot({
 
   return (
     <RenderProfile id={`DesktopMountedTabSlot:${tabDescriptor.kind}:${tabDescriptor.tabId}`}>
-      <View style={wrapperStyle}>
-        <WorkspacePaneContent
-          content={content}
-          isWorkspaceFocused={isWorkspaceFocused}
-          isPaneFocused={isPaneFocused}
-          onFocusPane={handleFocusPane}
-        />
-      </View>
+      <MountedTabActiveContext value={isVisible}>
+        <View style={wrapperStyle}>
+          <WorkspacePaneContent
+            content={content}
+            isWorkspaceFocused={isWorkspaceFocused}
+            isPaneFocused={isPaneFocused}
+            onFocusPane={handleFocusPane}
+          />
+        </View>
+      </MountedTabActiveContext>
     </RenderProfile>
   );
 });

packages/app/src/components/workspace-shortcut-targets-subscriber.tsx

@@ -20,14 +20,20 @@ export function WorkspaceShortcutTargetsSubscriber({
   serverId: string | null;
 }) {
   const { projects } = useSidebarWorkspacesList({ serverId, enabled });
-  const statusWorkspaces = useStatusModeWorkspaceEntries({
-    serverId: enabled ? serverId : null,
-    projects,
-  });
-  const projectNamesByKey = useProjectNamesMap(enabled ? serverId : null);
+  // groupMode must be resolved before gating the status-mode subscriptions below.
   const groupMode = useSidebarViewStore((state) =>
     enabled && serverId ? state.getGroupMode(serverId) : "project",
   );
+  // Only subscribe to agents/workspaces when the status-group view is actually active.
+  // In project mode (the default), these subscriptions would fire on every agent update
+  // (agents Map identity is replaced on every status transition) with no effect on
+  // the shortcut targets, causing ~15-46 wasted re-renders per agent switch.
+  const isStatusMode = enabled && groupMode === "status";
+  const statusWorkspaces = useStatusModeWorkspaceEntries({
+    serverId: isStatusMode ? serverId : null,
+    projects,
+  });
+  const projectNamesByKey = useProjectNamesMap(isStatusMode ? serverId : null);
   const collapsedProjectKeys = useSidebarCollapsedSectionsStore(
     (state) => state.collapsedProjectKeys,
   );