Yep, I used to have a few problems with my addons. Various windows would stop appearing or only partially appear, tree-style-tabs would have funny behaviour. I would assume it was because I was running the latest FF and the add-on hadn't caught up yet...

However, simply creating a new profile solved all my problems. Now, any time I run into an issue, I just create a new profile.

I know some people will simply suggest switching browser, but nothing handles hundreds or thousands of tabs better than firefox, and I'm not looking to change how I browse the web just to go easy on my browser...!