Comment 1 for bug 504912

I'm no expert at all but after some digging, I suspect some kind of conflict in the mouse/keyboard grabbing between GNOME Do and GNOME Screensaver. As far as I understand from this http://developer.gnome.org/doc/GGAD/sec-gdkcursor.html :

"To grab the pointer, call gdk_pointer_grab(), shown in Figure 8. The first argument [blah blah]

The final argument, time, specifies when the grab should take effect, in server time. This is intended to resolve conflicts if two clients try to grab the pointer simultaneously; the time must be after the last grab time, and it must not be in the future. Usually, you will want to use the time field from the event you're processing, or the GDK_CURRENT_TIME macro. GDK_CURRENT_TIME is a magic constant that tells the X server to substitute the current time. "

It seems that GNOME Do grabs mouse/keyboard (in Do.Interface/Windowing.cs ?) and then GNOME Screensaver is trying to do the same (probably here http://git.gnome.org/browse/gnome-screensaver/tree/src/gs-monitor.c ). Therefore I'm not entirely sure it is a GNOME Do problem.