fix(web): preserve search result titles in drag previews

apps/web/src/components/Sidebar.drag.browser.test.tsx

@@ -0,0 +1,83 @@
+import { createMemoryHistory } from "@tanstack/react-router";
+import { DEFAULT_CLIENT_SETTINGS } from "@t3tools/contracts/settings";
+import type * as Context from "effect/Context";
+import { expect, it, vi } from "vite-plus/test";
+import { page, userEvent } from "vite-plus/test/browser";
+
+import { AppRoot } from "~/AppRoot";
+// The thread route loads ChatView lazily; its first transform would eat the test's timeout.
+import "~/components/ChatView";
+import { __setClientSettingsForTests } from "~/hooks/useSettings";
+import { getRouter } from "~/router";
+import {
+  ENVIRONMENT_ID,
+  installFakeEnvironment,
+  threadWithHistory,
+  type FakeDriver,
+} from "../../test/fakeEnvironment";
+import { act, render } from "../../test/render";
+
+// The socket is the only fake layer; see test/appScenarios.renders.tsx.
+vi.mock("../../../../packages/client-runtime/src/connection/driver.ts", async (importOriginal) => {
+  const [actual, { fakeDriver }, Layer] = await Promise.all([
+    importOriginal<{ readonly ConnectionDriver: Context.Key<unknown, FakeDriver> }>(),
+    import("../../test/fakeEnvironment"),
+    import("effect/Layer"),
+  ]);
+  return { ...actual, layer: Layer.succeed(actual.ConnectionDriver, fakeDriver) };
+});
+
+vi.mock(import("~/rpc/requestLatencyState"), async (original) => ({
+  ...(await original()),
+  trackRpcRequestSent: () => {},
+}));
+
+it("keeps the title when dragging a search result from a collapsed folder", async () => {
+  await page.viewport(1400, 900);
+  const [first, second] = [threadWithHistory("visible", 1), threadWithHistory("search-target", 1)];
+  using _environment = installFakeEnvironment([first, second]);
+  __setClientSettingsForTests({
+    ...DEFAULT_CLIENT_SETTINGS,
+    boringSidebarEnabled: true,
+    onboardingCompletedAt: "2026-01-01T00:00:00.000Z",
+  });
+  const router = getRouter(
+    createMemoryHistory({ initialEntries: [`/${ENVIRONMENT_ID}/${first.id}`] }),
+  );
+  await router.load();
+  await using _app = await render(<AppRoot router={router} />, {
+    // AppRoot brings its own router.
+    router: false,
+  });
+  const folder = page.getByRole("button", { name: /^render/ });
+  await expect.element(folder).toHaveAttribute("aria-expanded", "true");
+  await userEvent.click(folder);
+  await expect.element(page.getByText(second.title, { exact: true })).not.toBeInTheDocument();
+  await userEvent.fill(page.getByRole("combobox", { name: "Search threads" }), "search-target");
+  const result = page.getByRole("option", { name: /Thread search-target/ });
+  await expect.element(result).toBeVisible();
+  const bounds = result.element().getBoundingClientRect();
+  const pointer = (type: string, x: number, y: number) =>
+    new PointerEvent(type, {
+      bubbles: true,
+      cancelable: true,
+      pointerId: 1,
+      isPrimary: true,
+      button: 0,
+      buttons: type === "pointerup" ? 0 : 1,
+      clientX: x,
+      clientY: y,
+    });
+  using _release = {
+    [Symbol.dispose]: () => document.dispatchEvent(pointer("pointerup", -100, 100)),
+  };
+  await act(() => {
+    result.element().dispatchEvent(pointer("pointerdown", bounds.x + 10, bounds.y + 10));
+    document.dispatchEvent(pointer("pointermove", -100, 100));
+  });
+  await vi.waitFor(() => {
+    expect(
+      document.querySelector('body > div[aria-hidden="true"].pointer-events-none')?.textContent,
+    ).toBe(second.title);
+  });
+});

apps/web/src/components/Sidebar.tsx

@@ -1765,8 +1765,8 @@ export default function Sidebar({ routeReveal }: { routeReveal: SidebarRouteReve
     }
     restoreDragScroll();
     const threads = contextDragThreads();
-    const title =
-      threadByKeyRef.current.get(contextDragKeyRef.current ?? "")?.title.trim() || "Thread";
+    const threadRef = parseScopedThreadKey(contextDragKeyRef.current ?? "");
+    const title = (threadRef && readThreadShell(threadRef)?.title.trim()) || "Thread";
     moveThreadContextDragGhost(point, { title, count: threads.length });
     return true;
   };