Although it happened twice this weekend, I cannot replicate the problem which means everything is good for now

It was my Window's desktop resolution.

I believe it may have had to so with creating new toons through ISBoxer for my second battlenet account, which seems to have problems the first time I log in to the toons (automatically puts game in full screen mode, other weird things).

Sorry to confuse things I'll update this thread if I can find out how to replicate the problem.