Issue 2602 - Don't use shadow DOM on mail.google.com, fixing an issue with the feedback form there

include.preload.js

 /*
  * This file is part of Adblock Plus <https://adblockplus.org/>,
  * Copyright (C) 2006-2015 Eyeo GmbH
  *
  * Adblock Plus is free software: you can redistribute it and/or modify
  * it under the terms of the GNU General Public License version 3 as
  * published by the Free Software Foundation.
  *
  * Adblock Plus is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
@@ skipping 177 matching lines @@
   var shadow = null;
   var style = null;
   var observer = null;
 
   // Use Shadow DOM if available to don't mess with web pages that rely on
   // the order of their own <style> tags (#309).
   //
   // However, creating a shadow root breaks running CSS transitions. So we
   // have to create the shadow root before transistions might start (#452).
   //
-  // Also, we can't use shadow DOM on Google Docs, since it breaks printing
-  // there (#1770).
-  if ("createShadowRoot" in document.documentElement && document.domain != "docs.google.com")
+  // Also, we can't use shadow DOM on Google Docs since it breaks printing
+  // there (#1770), and Google Mail since the feedback from breaks the layout
+  // there when using shadow DOM (#2602).
+  if ("createShadowRoot" in document.documentElement
+      && document.domain != "docs.google.com"
+      && document.domain != "mail.google.com")
   {
     shadow = document.documentElement.createShadowRoot();
     shadow.appendChild(document.createElement("shadow"));
   }
 
   var updateStylesheet = function(reinject)
   {
     ext.backgroundPage.sendMessage({type: "get-selectors"}, function(selectors)
     {
       if (observer)
@@ skipping 84 matching lines @@
   }, true);
 
   return updateStylesheet;
 }
 
 if (document instanceof HTMLDocument)
 {
   checkSitekey();
   window.updateStylesheet = init(document);
 }