diff -r 000000000000 -r 6474c204b198 browser/components/preferences/tabs.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/browser/components/preferences/tabs.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,66 @@
+# -*- Mode: Java; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*-
+# 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/.
+
+var gTabsPane = {
+
+  /*
+   * Preferences:
+   *
+   * browser.link.open_newwindow
+   * - determines where pages which would open in a new window are opened:
+   *     1 opens such links in the most recent window or tab,
+   *     2 opens such links in a new window,
+   *     3 opens such links in a new tab
+   * browser.tabs.loadInBackground
+   * - true if display should switch to a new tab which has been opened from a
+   *   link, false if display shouldn't switch
+   * browser.tabs.warnOnClose
+   * - true if when closing a window with multiple tabs the user is warned and
+   *   allowed to cancel the action, false to just close the window
+   * browser.tabs.warnOnOpen
+   * - true if the user should be warned if he attempts to open a lot of tabs at
+   *   once (e.g. a large folder of bookmarks), false otherwise
+   * browser.taskbar.previews.enable
+   * - true if tabs are to be shown in the Windows 7 taskbar
+   */
+
+#ifdef XP_WIN
+  /**
+   * Initialize any platform-specific UI.
+   */
+  init: function () {
+    const Cc = Components.classes;
+    const Ci = Components.interfaces;
+    try {
+      let sysInfo = Cc["@mozilla.org/system-info;1"].
+                    getService(Ci.nsIPropertyBag2);
+      let ver = parseFloat(sysInfo.getProperty("version"));
+      let showTabsInTaskbar = document.getElementById("showTabsInTaskbar");
+      showTabsInTaskbar.hidden = ver < 6.1;
+    } catch (ex) {}
+  },
+#endif
+
+  /**
+   * Determines where a link which opens a new window will open.
+   *
+   * @returns |true| if such links should be opened in new tabs
+   */
+  readLinkTarget: function() {
+    var openNewWindow = document.getElementById("browser.link.open_newwindow");
+    return openNewWindow.value != 2;
+  },
+
+  /**
+   * Determines where a link which opens a new window will open.
+   *
+   * @returns 2 if such links should be opened in new windows,
+   *          3 if such links should be opened in new tabs
+   */
+  writeLinkTarget: function() {
+    var linkTargeting = document.getElementById("linkTargeting");
+    return linkTargeting.checked ? 3 : 2;
+  }
+};