diff --git a/docs/browser-capture-harness.md b/docs/browser-capture-harness.md
index 594aacf5f6..f760fafa67 100644
--- a/docs/browser-capture-harness.md
+++ b/docs/browser-capture-harness.md
@@ -43,6 +43,18 @@ Run the shared browser profile fixture with:
 PASEO_CAPTURE_HARNESS_GROUP=browser-profile npm run capture-harness --workspace=@getpaseo/desktop
 ```
 
+On macOS, test native titlebar dragging after scrolling with:
+
+```bash
+PASEO_CAPTURE_HARNESS_GROUP=titlebar-drag npm run capture-harness --workspace=@getpaseo/desktop
+```
+
+This group needs Xcode Command Line Tools and Accessibility permission for the
+terminal running it. It sends real mouse input to its test window and checks
+window movement, including button clicks and a portal over the titlebar. Leave
+the mouse idle during this group. It reads the app's production CSS and writes
+screenshots and window bounds to the output directory.
+
 The browser profile group runs two Electron processes in sequence. It verifies that each
 renderer-side `did-attach` identity maps to the correct main-process guest, that two live
 tabs share cookies and local storage through one persistent session, and that the data is
diff --git a/packages/app/public/index.html b/packages/app/public/index.html
index f7116fc86b..a95e7b8c9e 100644
--- a/packages/app/public/index.html
+++ b/packages/app/public/index.html
@@ -70,6 +70,15 @@
         -webkit-app-region: no-drag !important;
       }
 
+      /* Electron does not clip app-region rectangles to scroll viewports.
+         Content-only viewports emit no window regions, including from their
+         controls. Visible controls here use normal DOM hit testing.
+         Use initial: Blink parses the explicit value none as no-drag. */
+      [data-window-content],
+      [data-window-content] * {
+        -webkit-app-region: initial !important;
+      }
+
       /* Suppress the browser's default focus outline — it appears on mouse
          clicks and looks out of place against our themed surfaces. Keep a
          themed ring for keyboard users via :focus-visible. */
diff --git a/packages/app/src/agent-stream/strategy-web.tsx b/packages/app/src/agent-stream/strategy-web.tsx
index 25e7a313d2..d0b7eda0df 100644
--- a/packages/app/src/agent-stream/strategy-web.tsx
+++ b/packages/app/src/agent-stream/strategy-web.tsx
@@ -1241,7 +1241,7 @@ function WebStreamViewport(props: StreamRenderInput & { isMobileBreakpoint: bool
     !liveAuxiliary;
 
   return (
-    <div style={viewportStyle}>
+    <div style={viewportStyle} data-window-content>
       <div
         ref={handleScrollContainerRef}
         data-testid="agent-chat-scroll"
diff --git a/packages/desktop/capture-harness/main.js b/packages/desktop/capture-harness/main.js
index 4beed26643..f657bfb2b6 100644
--- a/packages/desktop/capture-harness/main.js
+++ b/packages/desktop/capture-harness/main.js
@@ -2641,13 +2641,25 @@ async function runBrowserProfileGroup() {
 async function main() {
   ensureDirSync(OUT_DIR);
   if (
-    !["all", "existing", "permanent-parking", "automation", "browser-profile"].includes(
-      HARNESS_GROUP,
-    )
+    ![
+      "all",
+      "existing",
+      "permanent-parking",
+      "automation",
+      "browser-profile",
+      "titlebar-drag",
+    ].includes(HARNESS_GROUP)
   ) {
     fail(`unknown harness group ${HARNESS_GROUP}`);
   }
 
+  if (HARNESS_GROUP === "titlebar-drag") {
+    const { runTitlebarDragGroup } = require("./titlebar-drag.js");
+    await runTitlebarDragGroup(OUT_DIR);
+    pass(`capture harness titlebar-drag complete output=${OUT_DIR}`);
+    return;
+  }
+
   if (HARNESS_GROUP === "browser-profile") {
     const browserProfileResults = await runBrowserProfileGroup();
     await fsp.writeFile(
diff --git a/packages/desktop/capture-harness/titlebar-drag-mouse.m b/packages/desktop/capture-harness/titlebar-drag-mouse.m
new file mode 100644
index 0000000000..ac8894bc52
--- /dev/null
+++ b/packages/desktop/capture-harness/titlebar-drag-mouse.m
@@ -0,0 +1,52 @@
+// titlebar-drag-mouse.m — native mouse helper for the titlebar-drag harness.
+// Posts real CGEvents (kCGHIDEventTap) so a drag moves the actual window; pure
+// CDP input would never exercise Electron's draggable-region pipeline.
+// Usage: titlebar-drag-mouse drag x1 y1 x2 y2 | click x y
+// Every event carries flags 0 so a user-held Cmd/Opt cannot leak into the drag.
+// Exit 2 when this process lacks Accessibility trust: the harness fails loudly
+// instead of posting nothing and reading as a pass.
+#import <ApplicationServices/ApplicationServices.h>
+#import <stdio.h>
+#import <stdlib.h>
+#import <string.h>
+#import <unistd.h>
+
+static void post(CGEventType type, CGPoint p, useconds_t delay) {
+  CGEventRef event = CGEventCreateMouseEvent(NULL, type, p, kCGMouseButtonLeft);
+  if (!event) {
+    fprintf(stderr, "mouse: CGEventCreateMouseEvent failed\n");
+    exit(3);
+  }
+  CGEventSetFlags(event, (CGEventFlags)0);
+  CGEventPost(kCGHIDEventTap, event);
+  CFRelease(event);
+  usleep(delay);
+}
+
+int main(int argc, char **argv) {
+  if (!AXIsProcessTrusted()) {
+    fprintf(stderr, "mouse: not accessibility-trusted\n");
+    return 2;
+  }
+  if (argc == 6 && strcmp(argv[1], "drag") == 0) {
+    CGPoint a = {atof(argv[2]), atof(argv[3])};
+    CGPoint b = {atof(argv[4]), atof(argv[5])};
+    post(kCGEventMouseMoved, a, 150000);
+    post(kCGEventLeftMouseDown, a, 150000);
+    for (int i = 1; i <= 20; i++) {
+      CGPoint step = {a.x + (b.x - a.x) * i / 20, a.y + (b.y - a.y) * i / 20};
+      post(kCGEventLeftMouseDragged, step, 25000);
+    }
+    post(kCGEventLeftMouseUp, b, 25000);
+    return 0;
+  }
+  if (argc == 4 && strcmp(argv[1], "click") == 0) {
+    CGPoint p = {atof(argv[2]), atof(argv[3])};
+    post(kCGEventMouseMoved, p, 150000);
+    post(kCGEventLeftMouseDown, p, 150000);
+    post(kCGEventLeftMouseUp, p, 25000);
+    return 0;
+  }
+  fprintf(stderr, "usage: %s drag x1 y1 x2 y2 | click x y\n", argv[0]);
+  return 1;
+}
diff --git a/packages/desktop/capture-harness/titlebar-drag.js b/packages/desktop/capture-harness/titlebar-drag.js
new file mode 100644
index 0000000000..fe4a35d06c
--- /dev/null
+++ b/packages/desktop/capture-harness/titlebar-drag.js
@@ -0,0 +1,272 @@
+// Native mouse input is required: CDP mouse events do not move Electron windows.
+// Load production CSS so restoring the global no-drag rule reproduces the failure.
+const fs = require("node:fs");
+const fsp = require("node:fs/promises");
+const path = require("node:path");
+const { execFile } = require("node:child_process");
+const { promisify } = require("node:util");
+const { BrowserWindow } = require("electron");
+
+const execFileAsync = promisify(execFile);
+const PACKAGE_ROOT = path.join(__dirname, "..", "..");
+const INDEX_HTML = path.join(PACKAGE_ROOT, "app", "public", "index.html");
+const MOUSE_SOURCE = path.join(__dirname, "titlebar-drag-mouse.m");
+const BASE = { x: 100, y: 150 };
+const DRAG_DELTA = { x: 80, y: 50 };
+const DRAG_POINTS = [
+  { check: "header-overlay-blank", x: 625, y: 18 },
+  { check: "tab-row-overlay-blank", x: 625, y: 50 },
+  { check: "sidebar-overlay-blank", x: 125, y: 18 },
+  { check: "direct-rail-blank", x: 125, y: 50 },
+];
+const CLICK_POINTS = [
+  { check: "header-button-click", id: "header-btn", x: 955, y: 18 },
+  { check: "window-owned-toggle-click", id: "window-toggle", x: 40, y: 18 },
+  { check: "window-owned-focusable-click", id: "focusable", x: 320, y: 18 },
+  { check: "window-owned-negative-tabindex-button-click", id: "negative-button", x: 400, y: 18 },
+  { check: "sidebar-tab-click", id: "sidebar-btn", x: 205, y: 18 },
+  { check: "rail-tab-click", id: "rail-btn", x: 205, y: 50 },
+  { check: "portal-button-click", id: "portal-btn", x: 490, y: 18 },
+  { check: "floating-panel-button-click", id: "floating-btn", x: 785, y: 18 },
+];
+
+/** Static overlays and a sibling window control mirror the app shell ownership. */
+function buildFixtureHtml(appStyles) {
+  const dragOverlay =
+    'style="position:absolute;top:0;left:0;display:block;width:100%;height:100%;-webkit-app-region:drag"';
+  const button = (id, style) =>
+    `<button id="${id}" style="${style}" onclick="count('${id}')">${id}</button>`;
+  return `<!doctype html><html><head><meta charset="utf-8"><style>${appStyles}</style>
+<style>html,body{margin:0;width:100%;height:100%;background:#161616;color:#ddd;font:12px -apple-system,sans-serif;user-select:none}
+.pane{position:absolute}</style></head><body>
+<div class="pane" id="sidebar" style="left:0;top:0;width:250px;height:600px;background:#1d1d1d">
+  <div class="pane" style="left:0;top:0;width:250px;height:36px">
+    <div ${dragOverlay}></div>
+    ${button("sidebar-btn", "position:absolute;right:8px;top:6px;width:60px;height:24px")}
+  </div>
+  <div class="pane"
+       style="left:0;top:36px;width:250px;height:28px;-webkit-app-region:drag">
+    ${button("rail-btn", "position:absolute;right:8px;top:2px;width:60px;height:24px")}
+  </div>
+</div>
+<div class="pane" id="header" style="left:250px;top:0;width:750px;height:36px">
+  <div ${dragOverlay}></div>
+  ${button("header-btn", "position:absolute;right:8px;top:6px;width:60px;height:24px")}
+</div>
+<div class="pane" style="left:250px;top:36px;width:750px;height:28px">
+  <div ${dragOverlay}></div>
+</div>
+<!-- The sidebar toggle belongs to the window, outside every drag surface subtree. -->
+${button("window-toggle", "position:absolute;left:10px;top:6px;width:60px;height:24px;z-index:2")}
+<div id="focusable" tabindex="0" onclick="count('focusable')"
+     style="position:absolute;left:290px;top:6px;width:60px;height:24px;z-index:2">Focusable</div>
+<div id="negative-button" role="button" tabindex="-1" onclick="count('negative-button')"
+     style="position:absolute;left:370px;top:6px;width:60px;height:24px;z-index:2">Button</div>
+<div class="pane" id="chat-root" style="left:250px;top:64px;width:750px;height:536px;overflow:clip">
+  <div id="scroller" tabindex="-1" data-window-content
+       style="width:100%;height:100%;overflow-y:auto;overflow-x:clip;outline:none">
+    <div id="chat-inner" style="height:2000px;position:relative">
+      <a id="chat-link" href="#" onclick="event.preventDefault();count('chat-link')" style="position:absolute;left:250px;top:160px;width:180px;height:24px">Chat link</a>
+      ${button("chat-code", "position:absolute;left:250px;top:320px;width:180px;height:24px")}
+      <div id="chat-file" role="link" tabindex="0" onclick="count('chat-file')" style="position:absolute;left:250px;top:480px;width:180px;height:24px">file.ts</div>
+    </div>
+  </div>
+</div>
+<div id="overlay-root" style="position:fixed;inset:0;pointer-events:none;z-index:9999">
+  ${button("portal-btn", "position:fixed;left:460px;top:6px;width:60px;height:24px;pointer-events:auto")}
+</div>
+<div style="position:fixed;inset:0;pointer-events:none;z-index:9999">
+  ${button("floating-btn", "position:fixed;left:755px;top:6px;width:60px;height:24px;pointer-events:auto")}
+</div>
+<script>
+  window.__clicks = {};
+  window.count = (id) => { window.__clicks[id] = (window.__clicks[id] || 0) + 1; };
+  window.__fixture = {
+    setScroll(value) { document.getElementById("scroller").scrollTop = value; return this.snapshot(); },
+    placeControl(id, y) {
+      const control = document.getElementById(id);
+      const rect = control.getBoundingClientRect();
+      document.getElementById("scroller").scrollTop += rect.top + rect.height / 2 - y;
+      const placed = control.getBoundingClientRect();
+      return { x: placed.left + placed.width / 2, y: placed.top + placed.height / 2 };
+    },
+    snapshot() {
+      const inner = document.getElementById("chat-inner").getBoundingClientRect();
+      const clicks = { ...window.__clicks };
+      window.__clicks = {};
+      return { innerTop: inner.top, innerBottom: inner.bottom, clicks };
+    },
+  };
+</script></body></html>`;
+}
+
+function readRealAppStyles() {
+  const html = fs.readFileSync(INDEX_HTML, "utf8");
+  const styles = [...html.matchAll(/<style[^>]*>([\s\S]*?)<\/style>/g)].map((m) => m[1]).join("\n");
+  if (!styles.trim()) throw new Error(`no <style> blocks found in ${INDEX_HTML}`);
+  return styles;
+}
+
+async function compileMouseHelper(outDir) {
+  const binary = path.join(outDir, "titlebar-drag-mouse");
+  await execFileAsync("clang", [
+    "-O2",
+    "-o",
+    binary,
+    MOUSE_SOURCE,
+    "-framework",
+    "ApplicationServices",
+  ]);
+  return binary;
+}
+
+function samePosition(before, after) {
+  return before.x === after.x && before.y === after.y;
+}
+
+async function runTitlebarDragGroup(outDir) {
+  const results = [];
+  const record = (check, pass, detail) => {
+    results.push({ group: "titlebar-drag", check, pass, ...detail });
+    process.stdout.write(`${pass ? "PASS" : "FAIL"} titlebar-drag/${check}\n`);
+  };
+  let win = null;
+  let hardError = null;
+  try {
+    if (process.platform !== "darwin") {
+      throw new Error("titlebar-drag: macOS only — native window drag needs CGEventPost");
+    }
+    const mouse = await compileMouseHelper(outDir);
+    const fixturePath = path.join(outDir, "titlebar-drag-fixture.html");
+    await fsp.writeFile(fixturePath, buildFixtureHtml(readRealAppStyles()));
+
+    win = new BrowserWindow({
+      ...BASE,
+      width: 1000,
+      height: 600,
+      frame: false,
+      show: false,
+      backgroundColor: "#161616",
+    });
+    const evalPage = (code) => win.webContents.executeJavaScript(code);
+    const bounds = () => {
+      const current = win.getBounds();
+      return { x: current.x, y: current.y };
+    };
+    const resetPosition = async () => {
+      win.setPosition(BASE.x, BASE.y);
+      await new Promise((resolve) => setTimeout(resolve, 120));
+    };
+    const runMouse = async (args) => {
+      await execFileAsync(mouse, args.map(String));
+      await new Promise((resolve) => setTimeout(resolve, 220));
+    };
+    const mouseAt = (point) => ({ x: BASE.x + point.x, y: BASE.y + point.y });
+
+    await win.loadFile(fixturePath);
+    win.showInactive();
+    await new Promise((resolve) => setTimeout(resolve, 300));
+
+    for (const scrollTop of [0, 1000]) {
+      const snapshot = await evalPage(`window.__fixture.setScroll(${scrollTop})`);
+      const crossesHeader = snapshot.innerTop < 36 && snapshot.innerBottom > 0;
+      record(`scroll-${scrollTop}-content-crosses-header`, crossesHeader === (scrollTop === 1000), {
+        innerTop: snapshot.innerTop,
+        innerBottom: snapshot.innerBottom,
+      });
+      for (const point of DRAG_POINTS) {
+        await resetPosition();
+        const before = bounds();
+        const from = mouseAt(point);
+        await runMouse(["drag", from.x, from.y, from.x + DRAG_DELTA.x, from.y + DRAG_DELTA.y]);
+        const after = bounds();
+        const moved = after.x - before.x === DRAG_DELTA.x && after.y - before.y === DRAG_DELTA.y;
+        record(`scroll-${scrollTop}-${point.check}`, moved, { before, after });
+      }
+      const chatPoint = { x: 625, y: 300 };
+      await resetPosition();
+      const before = bounds();
+      const from = mouseAt(chatPoint);
+      await runMouse(["drag", from.x, from.y, from.x + DRAG_DELTA.x, from.y + DRAG_DELTA.y]);
+      const after = bounds();
+      record(`scroll-${scrollTop}-chat-area-does-not-drag`, samePosition(before, after), {
+        before,
+        after,
+      });
+    }
+
+    for (const point of CLICK_POINTS) {
+      await resetPosition();
+      const before = bounds();
+      const from = mouseAt(point);
+      await runMouse(["click", from.x, from.y]);
+      const { clicks } = await evalPage("window.__fixture.snapshot()");
+      const after = bounds();
+      const clicked = clicks[point.id] === 1;
+      const stillStationary = samePosition(before, after);
+      record(point.check, clicked && stillStationary, { clicks, before, after });
+      await runMouse(["drag", from.x, from.y, from.x + DRAG_DELTA.x, from.y + DRAG_DELTA.y]);
+      const afterDrag = bounds();
+      record(`${point.check}-does-not-drag`, samePosition(before, afterDrag), {
+        before,
+        after: afterDrag,
+      });
+    }
+
+    for (const id of ["chat-link", "chat-code", "chat-file"]) {
+      for (const y of [18, 50]) {
+        await resetPosition();
+        const point = await evalPage(`window.__fixture.placeControl(${JSON.stringify(id)}, ${y})`);
+        const before = bounds();
+        const from = mouseAt(point);
+        await runMouse(["drag", from.x, from.y, from.x + DRAG_DELTA.x, from.y + DRAG_DELTA.y]);
+        const after = bounds();
+        record(
+          `${id}-behind-header-${y}`,
+          after.x - before.x === DRAG_DELTA.x && after.y - before.y === DRAG_DELTA.y,
+          { before, after, point },
+        );
+      }
+      await resetPosition();
+      const point = await evalPage(`window.__fixture.placeControl(${JSON.stringify(id)}, 180)`);
+      const before = bounds();
+      const from = mouseAt(point);
+      await evalPage("window.__fixture.snapshot()");
+      await runMouse(["click", from.x, from.y]);
+      const { clicks } = await evalPage("window.__fixture.snapshot()");
+      const after = bounds();
+      record(`${id}-visible-click`, clicks[id] === 1 && samePosition(before, after), {
+        clicks,
+        before,
+        after,
+        point,
+      });
+      await runMouse(["drag", from.x, from.y, from.x + DRAG_DELTA.x, from.y + DRAG_DELTA.y]);
+      const afterDrag = bounds();
+      record(`${id}-visible-does-not-drag`, samePosition(before, afterDrag), {
+        before,
+        after: afterDrag,
+      });
+    }
+
+    const image = await win.webContents.capturePage();
+    await fsp.writeFile(path.join(outDir, "titlebar-drag.png"), image.toPNG());
+  } catch (error) {
+    hardError = error;
+    record("group-error", false, { reason: String(error?.message ?? error) });
+  } finally {
+    win?.destroy();
+  }
+
+  await fsp.writeFile(
+    path.join(outDir, "titlebar-drag-results.json"),
+    `${JSON.stringify({ generatedAt: new Date().toISOString(), results }, null, 2)}\n`,
+  );
+  const failed = results.filter((entry) => !entry.pass).map((entry) => entry.check);
+  if (hardError || failed.length > 0) {
+    throw new Error(`titlebar-drag group failed: ${failed.join(", ")}`, { cause: hardError });
+  }
+  return results;
+}
+
+module.exports = { runTitlebarDragGroup };
diff --git a/packages/desktop/e2e/workspace-restart.spec.ts b/packages/desktop/e2e/workspace-restart.spec.ts
index 36259bee4f..4ee1655242 100644
--- a/packages/desktop/e2e/workspace-restart.spec.ts
+++ b/packages/desktop/e2e/workspace-restart.spec.ts
@@ -6,6 +6,8 @@ import { getE2EDaemonPort } from "../../app/e2e/support/helpers/daemon-port";
 import { installDaemonWebSocketGate } from "../../app/e2e/support/helpers/daemon-websocket-gate";
 import { expectAppRoute } from "../../app/e2e/support/helpers/route-assertions";
 import { seedWorkspace } from "../../app/e2e/support/helpers/seed-client";
+import { openAgentRoute, seedMockAgentWorkspace } from "../../app/e2e/support/helpers/mock-agent";
+import { scrollAgentChatToBottom } from "../../app/e2e/support/helpers/agent-bottom-anchor";
 import { getServerId } from "../../app/e2e/support/helpers/server-id";
 import { waitForWorkspaceTabsVisible } from "../../app/e2e/support/helpers/workspace-tabs";
 import {
@@ -118,3 +120,131 @@ test("refresh keeps one continuous splash before restoring the desktop workspace
     await workspace.cleanup();
   }
 });
+
+function inspectChatDragExclusions(scroll: Element) {
+  const header = document.querySelector('[data-testid="composer-dock-header"]');
+  if (!header) throw new Error("Expected the workspace header");
+  const headerRect = header.getBoundingClientRect();
+  const headerY = headerRect.top + headerRect.height / 2;
+  const content = scroll.firstElementChild;
+  const focusScope = scroll.closest("[tabindex]");
+  if (!content || !focusScope) throw new Error("Expected chat content and its focus scope");
+  const contentRect = content.getBoundingClientRect();
+  const chatX = (contentRect.left + contentRect.right) / 2;
+  const tabRow = [...document.querySelectorAll('[data-testid="workspace-tabs-row"]')].find(
+    (row) => {
+      const rect = row.getBoundingClientRect();
+      return rect.left < chatX && rect.right > chatX && rect.height > 0;
+    },
+  );
+  if (!tabRow) throw new Error("Expected the chat pane's tab row");
+  const tabRect = tabRow.getBoundingClientRect();
+  const tabY = tabRect.top + tabRect.height / 2;
+  const exclusions = [...scroll.querySelectorAll("*")].filter((element) => {
+    const rect = element.getBoundingClientRect();
+    const style = getComputedStyle(element);
+    return (
+      style.visibility === "visible" &&
+      style.getPropertyValue("-webkit-app-region") === "no-drag" &&
+      ((rect.top < headerY && rect.bottom > headerY) || (rect.top < tabY && rect.bottom > tabY)) &&
+      rect.right > headerRect.left &&
+      rect.left < headerRect.right
+    );
+  });
+  return {
+    contentCrossesHeader: contentRect.top < headerY && contentRect.bottom > headerY,
+    contentCrossesTabRow: contentRect.top < tabY && contentRect.bottom > tabY,
+    focusScopeRegion: getComputedStyle(focusScope).getPropertyValue("-webkit-app-region"),
+    exclusions: exclusions.length,
+  };
+}
+
+test("scrolled chat does not exclude the workspace titlebar from dragging", async ({
+  page,
+}, testInfo) => {
+  const response = Array.from(
+    { length: 80 },
+    (_, index) =>
+      `Paragraph ${index}: a long conversation keeps the chat scrolled below its first message.\n\n[Drag reference](https://example.com) and [file.ts](./file.ts)\n\n\`\`\`ts\nconst item = ${index};\n\`\`\``,
+  ).join("\n\n");
+  const agent = await seedMockAgentWorkspace({
+    repoPrefix: "desktop-scrolled-chat-",
+    title: "Scrollable conversation",
+    initialPrompt: "Show a long response",
+    featureValues: { mockAssistantResponse: response },
+  });
+
+  try {
+    await agent.client.waitForFinish(agent.agentId, 15_000);
+    await installDesktopRuntime(page, {
+      serverId: getServerId(),
+      daemonListen: `127.0.0.1:${getE2EDaemonPort()}`,
+    });
+    await openAgentRoute(page, agent);
+    const chat = page.getByTestId("agent-chat-scroll");
+    await expect(chat).toBeVisible();
+
+    for (const colorScheme of ["light", "dark"] as const) {
+      await page.emulateMedia({ colorScheme });
+      await scrollAgentChatToBottom(page);
+      // Electron can subtract no-drag rectangles outside a scroll viewport's clip.
+      // Check the offending geometry, rather than DOM hit testing or a specific row style.
+      await expect
+        .poll(() => chat.evaluate(inspectChatDragExclusions))
+        .toEqual({
+          contentCrossesHeader: true,
+          contentCrossesTabRow: true,
+          focusScopeRegion: "no-drag",
+          exclusions: 0,
+        });
+    }
+
+    // Window-owned controls are siblings of workspace chrome, not descendants of it.
+    const closeMenu = page.getByRole("button", { name: "Close menu", exact: true });
+    await expect(closeMenu).toHaveCSS("-webkit-app-region", "no-drag");
+    await closeMenu.click();
+    const openMenu = page.getByRole("button", { name: "Open menu", exact: true });
+    await expect(openMenu).toHaveCSS("-webkit-app-region", "no-drag");
+    await openMenu.click();
+    await expect(closeMenu).toBeVisible();
+
+    const menuTrigger = page.getByTestId("workspace-header-menu-trigger");
+    await expect(menuTrigger).toHaveCSS("-webkit-app-region", "no-drag");
+    await menuTrigger.click();
+    const menu = page.getByTestId("workspace-header-menu");
+    await expect(menu).toBeVisible();
+    await expect(menu.getByRole("menuitem").first()).toHaveCSS("-webkit-app-region", "no-drag");
+    await page.keyboard.press("Escape");
+    await expect(menu).toBeHidden();
+    await page.getByRole("textbox", { name: "Message agent...", exact: true }).click();
+    // installDesktopRuntime supplies a macOS bridge, including shortcut identity.
+    await page.keyboard.press("Meta+f");
+    const find = page.getByRole("textbox", { name: "Find in pane", exact: true });
+    await expect(find).toBeFocused();
+    await expect(find).toHaveCSS("-webkit-app-region", "no-drag");
+    await find.fill("Paragraph 40:");
+    await expect(page.getByRole("status", { name: "Find matches" })).toHaveText("1 of 1");
+    for (const name of ["Next match", "Previous match", "Close Find"]) {
+      await expect(page.getByRole("button", { name, exact: true })).toHaveCSS(
+        "-webkit-app-region",
+        "no-drag",
+      );
+    }
+    await page.getByRole("button", { name: "Close Find", exact: true }).click();
+    await expect(find).toBeHidden();
+    await expect
+      .poll(() =>
+        chat.evaluate((scroll) => ({
+          focusReturned: document.activeElement?.contains(scroll),
+          tabindex: document.activeElement?.getAttribute("tabindex"),
+          appRegion: getComputedStyle(document.activeElement!).getPropertyValue(
+            "-webkit-app-region",
+          ),
+        })),
+      )
+      .toEqual({ focusReturned: true, tabindex: "-1", appRegion: "no-drag" });
+    await page.screenshot({ path: testInfo.outputPath("scrolled-chat-titlebar.png") });
+  } finally {
+    await agent.cleanup();
+  }
+});