Nah, I think its a common bug lately. Im on 4.5 and experience similar issues. Mostly on a render or running fcheck, but now that you mentioned it, it sometimes locks up when switching viewpanels to and from full screen.

I also am running a Radeon card. Could it be that the latest drivers just aren't compatible with Maya? I'm going to try and install the original drivers to see if that fixes things. I'll post on the results.

Im going to try reinstalling Maya first to see what happens. If no luck, then I'll go for the video drivers downgrade.