Gunnar Evermann <Gunnar.Evermann(a)nats.informatik.uni-hamburg.de&gt; writes: The race condition is here. There is _no_ general purpose way you can avoid it in an application -- potentially any other application can delete the window between the time you do the query pointer and then ask for the translate coordinates. To get around the problem, you (mentally) acknowledge that there is no way you can avoid the problem in your application. Instead you install an error handler that says -- "Oh, a bad window error, I'll ignore that". Do the translate coordinates, uninstall the error handler, and check if the error handler indicated an error. I'd be surprised if XEmacs didn't have something to do this automatically. --pete