On my F7 box, I've deleted gnome-screensaver and installed xscreensaver. I also have Beryl installed.

If I don't start Beryl, xscreensaver works fine - I can always get my desktop back with a mouse move or key press. If I start Beryl, xsceeensaver works fine for a while (about half an hour), but eventually, the screen goes black and then I can't restore my desktop. I still have a movable mouse cursor, but the box is unresponsive to mouse button or keyboard presses.

Does anyone have a suggestion about where the problem is, and how it might be fixed? I have seen forum threads which suggest this might be a X11 problem...