I too have seen this for a couple of 2011 SP's. I reported it to my VAR and they had seen it as weill. Now that I think about it, I didn't get a notice saying an SPR had been created for it. I'll have to follow up with them. I just started using 2012 SP 0 on a test machine, I'll keep an eye out for it. The way I have been fixing it is to un-maximize the model window (not the program) and then maximize it. It's really annoying and happens all the time, not just once or twice a day but typically every time I switch between windows.