Doesn't work properly in Firefox 13 (now works) Rated 5 out of 5 stars

Is this add-on supposed to work in Firefox 13? When using it with this version I have the problem that the tabs don't have any background (i.e. the background is completely transparent making the text hard to read). Popups such as the context menu and tooltips also have no background but a huge black border. The Firefox menu only has a background on its right half.
This only happens in Firefox 13 on my Windows machine. I also have a Linux machine with Firefox 12 set up where the problem doesn't appear. Both profiles are synced via Firefox sync.

EDIT: Said nothing. I had tried a development release which didn't solve the problem and then went back to the latest reviewed version which of course also had the problem. Now after some time I discovered there is an even newer unreviewed version which works like a charm. :-)

This review is for a previous version of the add-on (4.1.7).  This user has a previous review of this add-on.