Unredirect Fullscreen - XGL (nvidia)

[Ace2016]

I'm using xgl, when i enable unredirect fullscreen i used to get a massive speed boost but now fullscreen no longer works. If flashplayer goes fullscreen it immediately drops back out and if mplayer (patched) goes fullscreen the whole screen is black

Any ideas on how i can fix this?

BTW - xgl seems a lot smoother and much more responsive than plain old xorg so i will not be switching to xorg.

Thanks