upgrade to jaunty, tried dual head, lost compositing

hi,
i upgraded my aao to jaunty. i tried out the new dual monitor feature and it works nicely, but it doesn't allow screen compositing, so no AWN or desktop effects. I went back to single display and now, i still can't get screen compositing any ideas why?? i need awn and conky and exploding windows!
when i go to appearance > visual effects and try to select custom, it tells me "Desktop effects could not be enabled".
any help is appreciated.
thanks
peter

aao 110l, 1.5gb ram, 40gb hdd, sickboy 2.6.28 kernel

 

Maybe during this change your /etc/X11/xorg.conf got some new lines regarding a virtual desktop size. If it is greater than 2048x2048, it cannot handle compositing.

To avoid this behaviour remove those lines (or search for a suitable xorg.conf backup), and when you define the dual head layout try to do so by setting both screens in a position not leading to a higher than 2048x2048 resolution. I set mine one above the other.

By the way, in jaunty you can use Fn+F5 to switch between several multi-display configurations. It could be enough for your needs.