Return from fullscreen -> black screen with mouse

everytime I play a game in fullscreen (no matter what game, assault cube, sauerbraten, supertuxkart, hedgewars) and then quit the game and want to return to my Desktop, I only see a black screen and the mouse, I can hit CTRL + ALT + DEL and ENTER which logs me off, I can hear the KDE logout sound, I cant see the menu though.

Is anyone able to help?

Using OpenSUSE 11.2 with KDE.