I've just recently got a new Graphics card, an Galaxy NVIDIA GeForce GT 640, and this is where this bug occurred, every time when I hit F11 to turn ON fullscreen, the game crashes, with a black screen w/ junk at the bottom, sometimes just freezing, this only happens when I am in a world, including SMP, and I have to Command-Shift-Esc to get out of the mess. I did NOT get a crash log from this, or even a log. The Black screen is a rendering issue most likely.