Fixed: Pop-ups loading a different page after about:blank aren`t being considered

popupBlocker.js

 /*
  * This file is part of the Adblock Plus extension,
  * Copyright (C) 2006-2012 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 26 matching lines @@
 {
   if (!(tabId in tabsLoading))
   {
     // Not a pop-up we've previously seen
     return;
   }
 
   if ("url" in changeInfo)
     checkPotentialPopup(tabId, tab.url, tabsLoading[tabId]);
 
-  if ("status" in changeInfo && changeInfo.status == "complete")
+  if ("status" in changeInfo && changeInfo.status == "complete" && tab.url != "about:blank")
     delete tabsLoading[tabId];
 });
 
 
 function checkPotentialPopup(tabId, url, opener)
 {
   var requestHost = extractHostFromURL(url);
   var documentHost = extractHostFromURL(opener);
   var thirdParty = isThirdParty(requestHost, documentHost);
   var filter = defaultMatcher.matchesAny(url || "about:blank", "POPUP", documentHost, thirdParty);
   if (filter instanceof BlockingFilter)
     chrome.tabs.remove(tabId);
 }