Issue 3459 - Don't duplicate content type definition

chrome/content/ui/composer.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 101 matching lines @@
   {
     // IOService returned nsIURI - not much we can do with it
     addSuggestion(item.location);
     E("patternGroup").value = "";
   }
   if (Prefs.composer_default == 0)
     E("customPattern").focus();
   else
     E("patternGroup").focus();
 
-  let types = Array.from(Policy.contentTypes);
+  let types = Array.from(new Set(Policy.contentTypes.values()));
   types.sort();
 
   let docDomain = item.docDomain;
   let thirdParty = item.thirdParty;
 
   if (docDomain)
     docDomain = docDomain.replace(/^www\./i, "").replace(/\.+$/, "");
   if (docDomain)
     E("domainRestriction").value = docDomain;
 
@@ skipping 260 matching lines @@
  * Selects or unselects all type checkboxes except those
  * that are disabled.
  */
 function selectAllTypes(/**Boolean*/ select)
 {
   for (let typeNode = E("typeGroup").firstChild; typeNode; typeNode = typeNode.nextSibling)
     if (typeNode.getAttribute("disabled") != "true")
       typeNode.checked = select;
   updateFilter();
 }