diff --git a/.changeset/host-window-popout.md b/.changeset/host-window-popout.md
deleted file mode 100644
index d7e0d484..00000000
--- a/.changeset/host-window-popout.md
+++ /dev/null
@@ -1,18 +0,0 @@
----
-"aicodeman": minor
----
-
-feat(mobile): pop a session or a file preview out beside the dashboard from a native wrapper
-
-A WebView app has no browser pop-ups, so "Open in a new window" had nothing to open on a
-phone, and mobile.css hid it there. An embedding app that can put a page in a window of its
-own (an Android app on a foldable or in split screen) now says so with
-`window.CodemanHost.openWindow(absoluteUrl)`, returning whether a window opened. When it is
-present, the tab pop-out, the file viewer's detach button and a web tab's "open externally"
-go through it, and the tab's pop-out icon defaults on and shows at tablet widths (phone tabs
-keep their gear + close tap zones, so the host offers the pop-out from its own chrome through
-`app.detachSession`). The dashboard
-tracks such a window over the existing window channel, the path a reloaded dashboard already
-uses, and a solo window closes and raises itself through the optional
-`CodemanHost.closeWindow()` / `CodemanHost.focusWindow()`. Browsers define none of these, so
-nothing changes there.
diff --git a/docs/versioning-policy.md b/docs/versioning-policy.md
index 4e635d07..6ec92a2f 100644
--- a/docs/versioning-policy.md
+++ b/docs/versioning-policy.md
@@ -57,8 +57,10 @@ These may change in a **MINOR** (or even PATCH) release without a MAJOR bump:
    programmatically is not supported (there is no stable library entry point).
 3. **Experimental / opt-in features**, regardless of the app's version:
    Gesture Control (beta), Agent Teams
-   (`CLAUDE_CODE_EXPERIMENTAL_AGENT_TEAMS=1`), and anything labeled experimental
-   in the UI or docs. These may change or be removed at any time.
+   (`CLAUDE_CODE_EXPERIMENTAL_AGENT_TEAMS=1`), the native-wrapper window bridge
+   (`window.CodemanHost.openWindow` / `closeWindow` / `focusWindow`), and
+   anything labeled experimental in the UI or docs. These may change or be
+   removed at any time.
 
 ## Deprecation policy
 
diff --git a/src/web/public/app.js b/src/web/public/app.js
index 71f1cacc..075d3c14 100644
--- a/src/web/public/app.js
+++ b/src/web/public/app.js
@@ -1673,8 +1673,11 @@ class CodemanApp {
     // open the solo URL in a window of its own, beside this one on a foldable or
     // a split screen. There is no WindowProxy to poll, so the tab is tracked the
     // way a dashboard reload tracks it: the solo window's channel announcements
-    // plus the roll-call liveness check.
-    const hosted = this.openInHostWindow(CodemanBase.url('/session/' + encodeURIComponent(id)));
+    // plus the roll-call liveness check. Without a channel there is no roll-call
+    // either, so a hosted tab could never re-dock: refuse before asking the host.
+    const hosted = this.hasHostWindows() && !this.windowChannel
+      ? false
+      : this.openInHostWindow(CodemanBase.url('/session/' + encodeURIComponent(id)));
     if (hosted !== null) {
       if (!hosted) {
         this.showToast?.('Could not open a new window for this session', 'error');
@@ -1700,8 +1703,8 @@ class CodemanApp {
 
   /**
    * The embedding app's window opener, when there is one. A native wrapper
-   * exposes `window.CodemanHost.openWindow(absoluteUrl)` (returning whether a
-   * window opened) to say it can put a page in a window of its own; browsers
+   * exposes `window.CodemanHost.openWindow(absoluteUrl)` (anything but false
+   * counts as opened) to say it can put a page in a window of its own; browsers
    * never define it.
    * @returns {boolean} whether a host window opener is present
    */
@@ -1712,7 +1715,19 @@ class CodemanApp {
   }
 
   /**
-   * Open a same-origin page in a host window.
+   * The tab pop-out setting, defaulting ON under a host that opens windows.
+   * The one resolver for the tab icon, App Settings and the tab action menu.
+   * @param {object} settings stored per-device App Settings
+   * @param {object} [defaults] the device's default settings
+   * @returns {boolean} whether the pop-out control shows
+   */
+  tabDetachButtonEnabled(settings, defaults = {}) {
+    return settings?.showTabDetachButton ?? (this.hasHostWindows() || (defaults?.showTabDetachButton ?? false));
+  }
+
+  /**
+   * Open an http(s) URL in a host window, usually Codeman's own origin (a saved
+   * web tab passes its own).
    * @param {string} url absolute or base-relative URL
    * @returns {boolean|null} null when there is no host (use window.open),
    *   otherwise whether the host opened a window
@@ -1949,7 +1964,7 @@ class CodemanApp {
     el.className = 'solo-gone-overlay';
     el.innerHTML = '<h2>Session unavailable</h2>'
       + '<p>This session has ended or is no longer available.</p>'
-      + '<button class="btn-primary" onclick="window.close()">Close window</button>';
+      + '<button class="btn-primary" onclick="app._closeSoloWindow()">Close window</button>';
     document.body.appendChild(el);
     document.title = (window.codemanT?.('Session ended') || 'Session ended')
       + ' — ' + (window.CodemanI18n?.displayName || 'Codeman');
diff --git a/src/web/public/settings-ui.js b/src/web/public/settings-ui.js
index c8ffd4bd..b1ec2194 100644
--- a/src/web/public/settings-ui.js
+++ b/src/web/public/settings-ui.js
@@ -507,7 +507,8 @@ Object.assign(CodemanApp.prototype, {
     document.getElementById('appSettingsTabArrangement').value = this.resolveTabArrangement(settings);
     document.getElementById('appSettingsTabStateOrder').value = this.resolveTabStateOrder(settings);
     document.getElementById('appSettingsShowTabDetachButton').checked =
-      settings.showTabDetachButton ?? (this.hasHostWindows?.() ? true : (defaults.showTabDetachButton ?? false));
+      this.tabDetachButtonEnabled?.(settings, defaults)
+      ?? (settings.showTabDetachButton ?? defaults.showTabDetachButton ?? false);
     document.getElementById('appSettingsSessionListLayout').value =
       settings.sessionListLayout ?? defaults.sessionListLayout ?? 'header';
     const sessionSidebarFontSize = this.resolveSessionSidebarFontSize(
@@ -3725,7 +3726,8 @@ Object.assign(CodemanApp.prototype, {
     // Under a host that opens windows (see hasHostWindows) popping out is the
     // way to get two panes side by side, so the button defaults on there.
     const showTabDetach =
-      settings.showTabDetachButton ?? (this.hasHostWindows?.() ? true : (defaults.showTabDetachButton ?? false));
+      this.tabDetachButtonEnabled?.(settings, defaults)
+      ?? (settings.showTabDetachButton ?? defaults.showTabDetachButton ?? false);
     document.documentElement.classList.toggle('tabs-show-detach', showTabDetach);
     const compactHeader = MobileDetection.getDeviceType() !== 'desktop';
     const showFontControls = compactHeader ? false : (settings.showFontControls ?? defaults.showFontControls ?? false);
diff --git a/src/web/public/tab-rail-resize.js b/src/web/public/tab-rail-resize.js
index ae906641..81e89211 100644
--- a/src/web/public/tab-rail-resize.js
+++ b/src/web/public/tab-rail-resize.js
@@ -329,7 +329,8 @@ Object.assign(CodemanApp.prototype, {
       { label: 'Session options', run: () => this.openSessionOptions(sessionId) },
       // Group placement (vertical rail with a tab layout only; [] elsewhere).
       ...(this._tabRefMoveActions?.({ kind: 'session', id: sessionId }) || []),
-      ...(settings.showTabDetachButton || this.detachedSessions?.has(sessionId)
+      ...((this.tabDetachButtonEnabled?.(settings) ?? settings.showTabDetachButton) ||
+      this.detachedSessions?.has(sessionId)
         ? [{ label: 'Open in a new window', run: () => this.detachSession(sessionId) }]
         : []),
       { label: 'Close session', className: 'danger', run: () => this.requestCloseSession(sessionId) },
diff --git a/src/web/public/webview-tabs.js b/src/web/public/webview-tabs.js
index 0cbf2a7d..7c3876f6 100644
--- a/src/web/public/webview-tabs.js
+++ b/src/web/public/webview-tabs.js
@@ -515,7 +515,13 @@ Object.assign(CodemanApp.prototype, {
   openWebviewExternal(id) {
     const webview = this.webviews.get(id || this.activeWebviewId);
     if (!webview) return;
-    if (this.openInHostWindow?.(webview.url)) return;
+    // A host that refuses must not fall through to window.open, which in a
+    // WebView can replace the dashboard page.
+    const hosted = this.openInHostWindow?.(webview.url) ?? null;
+    if (hosted !== null) {
+      if (!hosted) this.showToast('Could not open a new window for this dashboard', 'error');
+      return;
+    }
     window.open(webview.url, '_blank', 'noopener');
   },
 
diff --git a/test/host-window-detach.test.ts b/test/host-window-detach.test.ts
index 59b67aa8..f840c203 100644
--- a/test/host-window-detach.test.ts
+++ b/test/host-window-detach.test.ts
@@ -11,7 +11,9 @@
  *      already uses),
  *   2. a host that refuses leaves the tab docked and toasts,
  *   3. without a host nothing changes (`openInHostWindow` returns null),
- *   4. a solo window closes and raises itself through the host when it can.
+ *   4. a solo window closes and raises itself through the host when it can,
+ *   5. without a window channel (no BroadcastChannel) the host is never asked,
+ *      since a hosted tab could not re-dock without the roll-call.
  *
  * Loaded via `vm` with a stubbed context (no jsdom — see connection-indicator.test.ts).
  */
@@ -58,6 +60,8 @@ function load(host?: Record<string, unknown>) {
   app.sessions = new Map([['s1', {}]]);
   app.detachedSessions = new Set();
   app.detachedWindows = new Map();
+  // A live window channel, as _initWindowChannel would open in a browser.
+  app.windowChannel = {};
   app.$ = () => null;
   app.showToast = vi.fn();
   app._postWindowMessage = vi.fn();
@@ -90,6 +94,19 @@ describe('detach through a host window opener', () => {
     expect(app.showToast).toHaveBeenCalledWith(expect.stringContaining('Could not open'), 'error');
   });
 
+  it('refuses without a window channel, so the tab is never stuck detached', () => {
+    const openWindow = vi.fn().mockReturnValue(true);
+    const { app, windowStub } = load({ openWindow });
+    app.windowChannel = null;
+
+    app.detachSession('s1');
+
+    expect(openWindow).not.toHaveBeenCalled();
+    expect(windowStub.open).not.toHaveBeenCalled();
+    expect(app.detachedSessions.size).toBe(0);
+    expect(app.showToast).toHaveBeenCalledWith(expect.stringContaining('Could not open'), 'error');
+  });
+
   it('treats a throwing host as a failed open', () => {
     const { app } = load({
       openWindow: () => {