Issue 1606 - Don't create overlays for hidden elements

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 182 matching lines @@
 // Adds an overlay to an element, which is probably a Flash object
 function addElementOverlay(elt) {
   // If this element is enclosed in an object tag, we prefer to block that instead
   if(!elt)
     return null;
 
   // If element doesn't have at least one of class name, ID or URL, give up
   // because we don't know how to construct a filter rule for it
   if(!hasFilters(elt))
     return;
+
+  // If the element isn't rendered (since its or one of its ancestor's
+  // "diplay" property is "none"), the overlay wouldn't match the element.

[Wladimir Palant, 2014/11/26 13:10:18]

Nit: "display"

+  if (!elt.offsetParent)

[Wladimir Palant, 2014/11/26 13:10:18]

What about elements that use visibility:hidden or height:0? I think it makes
more sense to test offsetWidth == 0 || offsetHeight == 0.

[Sebastian Noack, 2014/11/26 13:15:07]

We don't have to bother about those. In that case the overlay will be placed as
expected, covering the area (if any) of the element it was created for.

However if display is set to none, and an overlay would be created, it would
cover random other elements.

+    return;
+
   var thisStyle = getComputedStyle(elt, null);
   var overlay = document.createElement('div');
   overlay.prisoner = elt;
   overlay.className = "__adblockplus__overlay";
   overlay.setAttribute('style', 'opacity:0.4; background-color:#ffffff; display:inline-box; ' + 'width:' + thisStyle.width + '; height:' + thisStyle.height + '; position:absolute; overflow:hidden; -webkit-box-sizing:border-box; z-index: 99999');
   var pos = getAbsolutePosition(elt);
   overlay.style.left = pos[0] + "px";
   overlay.style.top = pos[1] + "px";
   // elt.parentNode.appendChild(overlay, elt);
   document.body.appendChild(overlay);
@@ skipping 533 matching lines @@
         break;
       default:
         sendResponse({});
         break;
     }
   });
 
   if (window == window.top)
     ext.backgroundPage.sendMessage({type: "report-html-page"});
 }