evaluating the following results in an X Error on stderr. (Linux 2.0.35, Xfree86 3.3.2, fvwm2). (progn (setq f (make-frame)) (delete-frame f) (mouse-position)) xemacs: X Error of failed request: BadWindow (invalid Window parameter) Major opcode of failed request: 40 (X_TranslateCoords) Resource id in failed request: 0x8002cf Serial number of failed request: 1455 Current serial number in output stream: 1455 I guess this behaviour somehow depends on the Setup of X and the wm. I have seen similar errors on Solaris2.6 with CDE. This happens whenever I quit an ediff session and the control frame is deleted. This error goes away if you switch to synchronous X communication, therefore I think that the following is The Right Patch. Please be advised that I have absolutely *no* knowledge of X programming, so please review carefully and don't assume that I know what I'm doing... There is at least one other X error which occurs intermittently and complains about freeing some private colours or somesuch. I have not yet been able to reproduce this. But since this happened in all versions of XEmacs I have ever used and really looks kind of unprofessional, we should IMHO hunt this a bit more aggressively. One approach would be to stick an abort() into x_error_handler() for all beta versions. What do you X-experts (no pun intended) think? --- frame-x.c.orig Sat Jun 13 06:28:48 1998 +++ frame-x.c Sat Aug 15 23:47:11 1998 ＠＠ -2371,6 +2371,8 ＠＠ unsigned int keys_and_buttons; struct frame *f; + XSync(display, False); + if (XQueryPointer (display, RootWindow (display, DefaultScreen (display)), &root_window, &child_window, &root_x, &root_y, &win_x, &win_y, &keys_and_buttons) == False)