@@ -217,6 +217,45 @@ const TASK_ID = ScheduledTaskId.make("task-1");
 const AUTOMATION_PROMPT = "Triage the inbox\n\nLabel every new issue and close duplicates.";
 
 describe("MessagesTimeline work rows", () => {
+  it("keeps the worked-for heading in place when expanded at the bottom", async () => {
+    const props = baseProps();
+    const runId = RunId.make("completed-run");
+    const container = document.createElement("div");
+    container.style.cssText = "height: 600px; width: 900px; display: flex; flex-direction: column;";
+    await using screen = await render(
+      <MessagesTimeline
+        {...props}
+        timelineEntries={[
+          ...Array.from({ length: 12 }, (_, index) =>
+            message(`Earlier context ${index}`, {}, `context-${index}`),
+          ),
+          message("Progress details\n\n".repeat(50), { role: "assistant", runId }, "progress"),
+          message("Done", { role: "assistant", runId }, "final"),
+        ]}
+      />,
+      { container },
+    );
+    const heading = screen.getByRole("button", { name: /^Worked for/ });
+    await expect.element(heading).toBeVisible();
+    const viewport = props.listRef.current!.getScrollableNode()!;
+    await vi.waitFor(() =>
+      expect(viewport.scrollHeight - viewport.clientHeight - viewport.scrollTop).toBeLessThan(2),
+    );
+    expect(viewport.scrollTop).toBeGreaterThan(0);
+    const top = heading.element().getBoundingClientRect().top;
+    const height = viewport.scrollHeight;
+    using _timers = fakeTimers();
+    await heading.click();
+    await act(() => vi.advanceTimersByTime(1000));
+    await vi.waitFor(() => {
+      expect(viewport.scrollHeight).toBeGreaterThan(height + 500);
+      expect(heading.element().getBoundingClientRect().top).toBeCloseTo(top, 0);
+      expect(viewport.scrollHeight - viewport.clientHeight - viewport.scrollTop).toBeGreaterThan(
+        500,
+      );
+    });
+  });
+
   it.each(["delegated", "legacy", "missing"] as const)(
     "uses the reported task for %s completion notifications",
     async (source) => {
 
@@ -470,13 +470,6 @@ const ConversationTimeline = memo(function ConversationTimeline({
   const normalizedFindQuery = findQuery.trim();
   const findActive = findExpanded;
 
-  const disclosurePinsEndRef = useRef(false);
-  const pinDisclosureToEnd = () => {
-    if (!disclosurePinsEndRef.current) return;
-    const element = listRef.current?.getScrollableNode();
-    if (element) element.scrollTop = element.scrollHeight;
-  };
-
   const scheduleDisclosureSettle = () => {
     if (disclosureSettleFrameRef.current !== null) {
       cancelAnimationFrame(disclosureSettleFrameRef.current);
@@ -485,10 +478,7 @@ const ConversationTimeline = memo(function ConversationTimeline({
       cancelAnimationFrame(disclosureSettleSecondFrameRef.current);
     }
     disclosureSettleFrameRef.current = requestAnimationFrame(() => {
-      pinDisclosureToEnd();
       disclosureSettleSecondFrameRef.current = requestAnimationFrame(() => {
-        pinDisclosureToEnd();
-        disclosurePinsEndRef.current = false;
         disclosureAnchorKeyRef.current = null;
         setDisclosureToggleSettling(false);
         disclosureSettleFrameRef.current = null;
@@ -499,13 +489,11 @@ const ConversationTimeline = memo(function ConversationTimeline({
 
   const suspendEndScrollMaintenanceForDisclosure = (anchorKey: string) => {
     disclosureAnchorKeyRef.current = anchorKey;
-    disclosurePinsEndRef.current = resolveTimelineIsAtEnd(listRef.current?.getState()) === true;
     setDisclosureToggleSettling(true);
     scheduleDisclosureSettle();
   };
 
   const shouldRestoreVisibleContentPosition = (row: MessagesTimelineRow) => {
-    if (disclosurePinsEndRef.current) return false;
     const disclosureAnchorKey = disclosureAnchorKeyRef.current;
     return disclosureAnchorKey === null || row.id === disclosureAnchorKey;
   };
@@ -955,8 +943,7 @@ const ConversationTimeline = memo(function ConversationTimeline({
   };
 
   const handleItemSizeChanged = () => {
-    if (disclosurePinsEndRef.current) {
-      queueMicrotask(pinDisclosureToEnd);
+    if (disclosureAnchorKeyRef.current !== null) {
       scheduleDisclosureSettle();
     }
     scheduleMinimapRefresh();