And yes, the fix was the removal of "KHTMLFixes.css". More info: 1. [Bug 679971] remove Navigator.taintEnabled() <https://bugzilla.mozilla.org/show_bug.cgi?id=679971> 2. [Bug 31807] Firefox 9 dropped navigator.taintEnabled() <https://bugzilla.wikimedia.org/show_bug.cgi?id=31807>