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

chrome/browser/resources/shared/css/menu.css

 /* 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.
  */
 
 menu {
   -webkit-box-shadow: 0 2px 4px rgba(0, 0, 0, .50);
   background: white;
   color: black;
   cursor: default;
-  display: none;
   left: 0;
   margin: 0;
   outline: 1px solid rgba(0, 0, 0, 0.2);
   padding: 8px 0;
   position: fixed;
   white-space: nowrap;
   z-index: 3;
 }
 
+menu:not(.decorated) {
+  display: none;
+}
+
 menu > * {
   box-sizing: border-box;
   display: block;
   margin: 0;
   text-align: start;
   width: 100%;
 }
 
 menu > :not(hr) {
   -webkit-appearance: none;
@@ skipping 41 matching lines @@
   width: 9px;
 }
 
 menu > [checked] {
   -webkit-padding-start: 0;
 }
 
 menu > [selected][checked]:active:before {
   content: url('../images/checkbox_white.png');
 }