After a KDE application is closed, it lingers for 10 seconds and finally quits after printing this message: QClipboard: Unable to receive an event from the clipboard manager in a reasonable time Apologies if filed in the wrong section
That's unrelated to the window manager. Do you have the clipboard manager running btw?
FYI I can reproduce the problem too. *** This bug has been marked as a duplicate of bug 6521 ***