Stabilize sidebar activity toggle placement (#33648)

src/renderer/src/components/sidebar/SidebarHeader.tsx

@@ -56,7 +56,7 @@ const SidebarHeader = React.memo(function SidebarHeader({
   )
 
   return (
-    <div className="mt-2 flex h-8 min-w-0 items-center justify-between gap-1.5 px-2">
+    <div className="mt-2 flex h-8 min-w-0 shrink-0 items-center justify-between gap-1.5 px-2">
       <div className="flex min-w-0 items-center gap-1">
         <span
           // Truncate localized titles because fixed-width actions cannot shrink inside the short header row.
@@ -163,12 +163,10 @@ const SidebarHeader = React.memo(function SidebarHeader({
             </div>
           </PopoverContent>
         </Popover>
-        {agentsViewActive ? (
-          <div ref={activityOptionsTarget} className="flex items-center" />
-        ) : null}
         <SidebarHeaderActions
           onWorkspaceBoardMenuOpenChange={onWorkspaceBoardMenuOpenChange}
           agentsViewActive={agentsViewActive}
+          activityOptionsTarget={activityOptionsTarget}
         />
       </div>
     </div>

src/renderer/src/components/sidebar/sidebar-header-actions.tsx

@@ -78,20 +78,23 @@ function NewWorkspaceButton({
 
 export function SidebarHeaderActions({
   onWorkspaceBoardMenuOpenChange,
-  agentsViewActive = false
+  agentsViewActive = false,
+  activityOptionsTarget
 }: {
   onWorkspaceBoardMenuOpenChange: (open: boolean) => void
   agentsViewActive?: boolean
+  activityOptionsTarget?: React.Ref<HTMLDivElement>
 }): React.JSX.Element {
   return (
     <div className="flex shrink-0 items-center gap-1" data-sidebar-header-actions="">
-      {/* Activity portals its own options into this slot; retain Add project to avoid shifting other controls. */}
-      {agentsViewActive ? null : (
-        <SidebarWorkspaceOptionsMenu
-          preserveWorkspaceBoardOpen
-          onMenuOpenChange={onWorkspaceBoardMenuOpenChange}
-        />
-      )}
+      <div ref={activityOptionsTarget} className="flex size-6 shrink-0 items-center">
+        {agentsViewActive ? null : (
+          <SidebarWorkspaceOptionsMenu
+            preserveWorkspaceBoardOpen
+            onMenuOpenChange={onWorkspaceBoardMenuOpenChange}
+          />
+        )}
+      </div>
       <AddProjectButton preserveWorkspaceBoardOpen />
       <NewWorkspaceButton preserveWorkspaceBoardOpen />
     </div>