@Marek: I can't reply to that
(https://groups.google.com/forum/#!topic/qubes-users/2gaeTKuZEd4)
because I wasn't in the mailing list (now I am), sorry for that...
I wanted to install nvidia for gaming but after reading the UserFaq I
see that this wouldn't work at all. I'm not playing games very often so
I think multiboot wouldn't be so bad. The second system then will be my
"emergency" + gaming OS so no problem.
Now to my problem with flsh and fullscreen:
I have two monitors and they work out of the box with nouveau. But when
I switch flash videos to fullscreen it's like it stretches over both
monitors showing the video in the milddle except that it just shows on
one monitor. So one monitor still shows the desktop and the other shows
black border on the side and half of the video (sorry, don't know how I
can describe that better).
I searched a bit and found that Xinerama was a solution for some. So I
created a xorg.conf with Xinerama set to true but that didn't made a
difference.
I also enabled fullscreen for that VM.