Comment # 8 on bug 82533 from Kertesz Laszlo

(In reply to comment #5)
> Created attachment 104559 [details]
> Glxinfo
> 
> My current setup is: SLiM as login manager, Openbox as window manager, feh
> to show the desktop wallpaper, Xcompmgr for transparency, xfce4-panel for
> the panel.
> My autostart for Openbox is like this:
> feh --bg-scale /home/davide/Immagini/background.jpg &
> 
> if which xfce4-panel >/dev/null 2>&1; then
>   (sleep 2 && xcompmgr) &
>   (sleep 2 && xfce4-panel) &
> fi
> 
> I'm using linux 3.15.8, Mesa 10.2.5 and Xorg 1.16 on archlinux.

xcompmgr is a software compositing manager if im not mistaken. Try stopping it
before starting your games.