solved this with an option in xorg.conf

I put my relevant config here (I don't remember exactly what option was)

Section "Screen"
...
Option "AddARGBGLXVisuals" "True"
Option "DisableGLXRootClipping" "True"
Option "DamageEvents" "True"
Option "RenderAccel" "on"
Option "NvAGP" "1"
Option "XAANoOffscreenPixmaps"

do not forget to write also

Quote:
Section "Extensions"
Option "Composite" "Disable"
EndSection