Originally Posted by bones_was_here
I'm using a GTX275, kernel 126.96.36.199 (vanilla), xserver 1.7.7 and KDE 4.4.4 with KWin's composition enabled on Debian Sid.
What is UnredirectFullscreen=
set to in ~/.kde/share/config/kwinrc
for you ?
If it's not set do try with UnredirectFullscreen=true
( restart the X server after you modify this)