Compiz/unity got undirected fullscreen windows

yay.

And what does that mean?

If you run a non-windowed, fullscreen application then the compositing layer is entirely bypassed so no need for strange rules or manually disabling compositing to get full performance for games. This is a good thing.

I did cover some of this kind of thing previously with workarounds:
http://forums.xonotic.org/showthread.php?tid=2685

I did ask for this as a feature request for KWin but the response wasn't positive. Basically they don't want to do it unless someone has a fullscreened web browser or similar which might want to take advantage of compositing. I have to use KWin rules instead.