For the longest time my kdm wasn't working so the computer would always boot into console and I would start gnome by typing startx. In those days my dual screen actually worked quite well. Programs were smart enough to start on one monitor or the other and not spread themselves across both screens, When I maximized a program it would maximize to that screen, the task bar would only go across one screen. And, funny enough, I could use my keyboard shortcuts with amaroK even in Gnome. (Win + B to skip to next song)

Ever since I got kdm working again and starting Gnome through it, these nice features have stopped working. I discovered that the same thing happened if I used gdm. But when I 'rebreak' my kdm so I start up with no display manager, I get my nice xinerama features back. I'm also using the nvidia twin-view which uses it's own version of xinerama but provides standard xinerama extentions to the window manager. The nvidia logo is still displayed regardless of whether I use a display manager or not. Whats going on?

I think the problem is due to Xgl/compiz actually. I didn't think about it because I'm not using a compiz enabled gnome session at the moment, but I guess Xgl is still running?