Gunnar Evermann <Gunnar.Evermann(a)nats.informatik.uni-hamburg.de&gt; writes: Maybe you could move the call f = x_any_window_to_frame (d, win); if (!f) return 0; to before the loop. Since frames are biggest structures we support, if it is not a window of a frame there is no use iterating down anyway. I am not an X expert but from the look of things it seems it should work. Jan Why is the XSync solution not OK? Isn't the problem that we are getting return outdated information because Xt has a backlog processing events.