Use hidden attribute rather the 'display: none' for hiding menus.

chrome/browser/resources/ntp4/other_sessions.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.
 
 /**
  * @fileoverview The menu that shows tabs from sessions on other devices.
  */
 
 cr.define('ntp', function() {
   'use strict';
@@ skipping 37 matching lines @@
       this.menu = new Menu;
       cr.ui.decorate(this.menu, Menu);
       this.menu.classList.add('footer-menu');
       this.menu.addEventListener('contextmenu',
                                  this.onContextMenu_.bind(this), true);
       document.body.appendChild(this.menu);
 
       // Create the context menu that appears when the user right clicks
       // on a device name.
       this.deviceContextMenu_ = DeviceContextMenuController.getInstance().menu;
-      this.deviceContextMenu_.style.display = 'none';
       document.body.appendChild(this.deviceContextMenu_);
 
       this.promoMessage_ = $('other-sessions-promo-template').cloneNode(true);
       this.promoMessage_.removeAttribute('id');  // Prevent a duplicate id.
 
       this.sessions_ = [];
       this.anchorType = cr.ui.AnchorType.ABOVE;
       this.invertLeftRight = true;
 
       // Initialize the images for the drop-down buttons that appear beside the
@@ skipping 31 matching lines @@
         }
       }
     },
 
     /**
      * Hides the menu.
      * @override
      */
     hideMenu: function() {
       // Don't hide if the device context menu is currently showing.
-      if (this.deviceContextMenu_.style.display == 'none')
+      if (this.deviceContextMenu_.hidden)
         MenuButton.prototype.hideMenu.call(this);
     },
 
     /**
      * Shows the menu, first rebuilding it if necessary.
      * TODO(estade): the right of the menu should align with the right of the
      * button.
      * @override
      */
     showMenu: function() {
@@ skipping 229 matching lines @@
     updateMenuItems_: function() {
       this.collapseItem_.hidden = this.session_.collapsed;
       this.expandItem_.hidden = !this.session_.collapsed;
     }
   };
 
   return {
     OtherSessionsMenuButton: OtherSessionsMenuButton,
   };
 });