Issue 1609 - Handle the case of no selectors in "Block Element"

include.postload.js

 /*
  * 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 439 matching lines @@
   {
     var style = elt.getAttribute("style");
     if (style)
       addSelector(escapeCSS(elt.localName) + '[style=' + quote(style) + ']');
   }
 
   // Show popup
   clickHide_showDialog(e.clientX, e.clientY, clickHideFilters);
 
   // Highlight the elements specified by selector in yellow
-  highlightElements(selectorList.join(","));
+  if (selectorList.length > 0)
+    highlightElements(selectorList.join(","));
   // Now, actually highlight the element the user clicked on in red
   highlightElement(currentElement, "#fd1708", "#f6a1b5");
 
   // Make sure the browser doesn't handle this click
   e.preventDefault();
   e.stopPropagation();
 }
 
 function parseSrcSet(element)
 {
@@ skipping 240 matching lines @@
         break;
       default:
         sendResponse({});
         break;
     }
   });
 
   if (window == window.top)
     ext.backgroundPage.sendMessage({type: "report-html-page"});
 }