FF: JS error when inserting elements after HTML with comments.

[Jakub Ś]

Ticket has been reported on our support channel - Topic - "Possible bug: HTML comments cause Javascript error when integrating CKFinder with CKEditor"

1. Insert on of the following

   <!--A comment-->
   <div><!--A comment--></div>
   <div>Something else</div><!-- A comment -->
   <div><div>Something else</div><!-- A comment --></div>
   

2. Try to insert Image/Table/Link/Page break using toolbar buttons.
3. After pressing OK JS error pops out.

The error:
Message: startNode.getChildCount is not a function
Line: 792
URI: ckeditor/_source/core/dom/range.js

Bug is only reproducible in Firefox 4-8 (FF 3.6 is fine).

Ticket has been reproducible from CKE 3.6.1 rev [6963]