issue 1435 - Port popup.html from Chrome/Safari/Opera to Firefox

chrome/skin/popup.css

 /*
  * This file is part of Adblock Plus <http://adblockplus.org/>,
  * Copyright (C) 2006-2014 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 141 matching lines @@
 #clickhide-cancel .icon
 {
   background-position: -50px -33px;
 }
 
 #clickhide-instructions
 {
   margin: 10px 15px;
 }
 
-#blockable .icon, #blockable-close .icon
+#blockable .icon
 {
   background-position: -66px -17px;
+}
+
+#blockable:not(.open) [data-action="close"],
+#blockable.open [data-action="open"]
+{
+  display: none;
 }
 
 #report-issue .icon
 {
   background-position: -50px -81px;
 }
 
 label
 {
   vertical-align: middle;
 }