Mageia 2 freezes when using alt+tab quickly KDE

Hi!
When Mageia 2 came out, I immediately did a network update to upgrade my previous Mageia 1.
Since then I've been having some issues when using KDE. Whenever I try to change an application window with alt+Tab, if I release keys too quickly, desktop freezes out and I must do a hard reset (un-powering PC).
I'm using a Nvidia GTS 250 graphics card with Nvidia drivers. I have compiz active to give "nice" effects. This keeps on happening even when no 3D effect is on.
When I had Mageia 1 there was no such problems. I haven't tested yet on Gnome, though.
Hope somebody can tell me what could possibly be wrong.
When Mageia 2 came out, I immediately did a network update to upgrade my previous Mageia 1.
Since then I've been having some issues when using KDE. Whenever I try to change an application window with alt+Tab, if I release keys too quickly, desktop freezes out and I must do a hard reset (un-powering PC).
I'm using a Nvidia GTS 250 graphics card with Nvidia drivers. I have compiz active to give "nice" effects. This keeps on happening even when no 3D effect is on.
When I had Mageia 1 there was no such problems. I haven't tested yet on Gnome, though.
Hope somebody can tell me what could possibly be wrong.