Disables the ability to tab to navigation items when an overlay is displayed.

chrome/browser/resources/options2/options_page.js

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 cr.define('options', function() {
   /////////////////////////////////////////////////////////////////////////////
   // OptionsPage class:
 
   /**
    * Base class for options page.
@@ skipping 233 matching lines @@
 
     if (!overlay.visible) {
       overlay.visible = true;
       if (overlay.didShowPage) overlay.didShowPage();
     }
 
     // Update tab title.
     this.setTitle_(overlay.title);
     // Try to focus the first element of the new overlay.
     options.FocusManager.getInstance().focusFirstElement();
+    // Although FocusManager will correct erroneous focus in the settings frame,
+    // it only runs in that <iframe>, so it cannot ensure proper focus in the
+    // Uber frame where the navigation items reside. Thus, disable the ability
+    // for those items to be focused to prevent them from receiving focus in a
+    // page "behind" the overlay.
+    uber.invokeMethodOnParent('disableNavigationItemTabbing');

[Evan Stade, 2012/05/08 23:23:00]

this shouldn't be necessary. Just piggy back on beginInterceptingEvents

[Kyle Horimoto, 2012/05/08 23:44:18]

Done.

 
     return true;
   };
 
   /**
    * Returns whether or not an overlay is visible.
    * @return {boolean} True if an overlay is visible.
    * @private
    */
   OptionsPage.isOverlayVisible_ = function() {
@@ skipping 28 matching lines @@
     overlay.visible = false;
 
     if (overlay.didClosePage) overlay.didClosePage();
     this.updateHistoryState_(false, {ignoreHash: true});
 
     // Another page or overlay will now be displayed. If it previously had a
     // focused element, restore this element's focus.
     var currentPage = this.getTopmostVisiblePage();
     if (currentPage.lastFocusedElement)
       currentPage.lastFocusedElement.focus();
+
+    // If the last overlay has just been closed, there is no longer an overlay
+    // to block the navigation elements, so allow them to receive focus.
+    if (!this.isOverlayVisible_())
+      uber.invokeMethodOnParent('enableNavigationItemTabbing');
   };
 
   /**
    * Cancels (closes) the overlay, due to the user pressing <Esc>.
    */
   OptionsPage.cancelOverlay = function() {
     // Blur the active element to ensure any changed pref value is saved.
     document.activeElement.blur();
     var overlay = this.getVisibleOverlay_();
     // Let the overlay handle the <Esc> if it wants to.
@@ skipping 557 matching lines @@
     canShowPage: function() {
       return true;
     },
   };
 
   // Export
   return {
     OptionsPage: OptionsPage
   };
 });