diff -r 000000000000 -r 6474c204b198 addon-sdk/source/lib/sdk/panel/window.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/addon-sdk/source/lib/sdk/panel/window.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,61 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+'use strict';
+
+// The panel module currently supports only Firefox.
+// See: https://bugzilla.mozilla.org/show_bug.cgi?id=jetpack-panel-apps
+module.metadata = {
+  'stability': 'unstable',
+  'engines': {
+    'Firefox': '*'
+  }
+};
+
+const { getMostRecentBrowserWindow, windows: getWindows } = require('../window/utils');
+const { ignoreWindow } = require('../private-browsing/utils');
+const { isPrivateBrowsingSupported } = require('../self');
+const { isGlobalPBSupported } = require('../private-browsing/utils');
+
+function getWindow(anchor) {
+  let window;
+  let windows = getWindows("navigator:browser", {
+    includePrivate: isPrivateBrowsingSupported || isGlobalPBSupported
+  });
+
+  if (anchor) {
+    let anchorWindow = anchor.ownerDocument.defaultView.top;
+    let anchorDocument = anchorWindow.document;
+
+    // loop thru supported windows
+    for each(let enumWindow in windows) {
+      // Check if the anchor is in this browser window.
+      if (enumWindow == anchorWindow) {
+        window = anchorWindow;
+        break;
+      }
+
+      // Check if the anchor is in a browser tab in this browser window.
+      let browser = enumWindow.gBrowser.getBrowserForDocument(anchorDocument);
+      if (browser) {
+        window = enumWindow;
+        break;
+      }
+
+      // Look in other subdocuments (sidebar, etc.)?
+    }
+  }
+
+  // If we didn't find the anchor's window (or we have no anchor),
+  // return the most recent browser window.
+  if (!window)
+    window = getMostRecentBrowserWindow();
+
+  // if the window is not supported, then it should be ignored
+  if (ignoreWindow(window)) {
+  	return null;
+  }
+
+  return window;
+}
+exports.getWindow = getWindow;