Recent change was for the worse Noté 3 sur 5 étoiles

This used to be the best looking theme out there. The change on March 27, 2012 was applied automatically without even asking for a confirmation. The new look is not nearly as good. I would like to roll back to the old look. Short of using System Restore, is this possible?

Note: I have Firefox 11 set to NOT automatically update. But apparently that doesn't affect add-ons. To change the add-on setting, you have to click on the little gear in the Add-ons Manager. And the only options Firefox 11 gives you are a) Download and apply updates automatically without asking, or b) Don't even notify me that updates exist. There is no option to notify me of updates and let me decide whether to install them. And there is no option to roll back the settings if an "update" turns out to be a disaster. That's not this add-on's fault, of course. But it sure compounds the problem.