more details: I can cause the hang simply by selecting a large piece of text in an xemacs with a running *background-1* buffer that has a process generating a fair bit of output then pasting it continuously (via middle mouse button) into a Mozilla compose mail window. I used xwininfo to lookup the window that was reportedly causing the error - it doesn't appear to exist. Hope that helps, Jules xemacs: X Error of failed request: BadWindow (invalid Window parameter) Major opcode of failed request: 25 (X_SendEvent) Resource id in failed request: 0x2419af8 Serial number of failed request: 1262037 Current serial number in output stream: 1262038 Xlib: unexpected async reply (sequence 0x1341d6)! xemacs: X Error of failed request: BadWindow (invalid Window parameter) Major opcode of failed request: 18 (X_ChangeProperty) Resource id in failed request: 0x2419af8 Serial number of failed request: 1262036 Current serial number in output stream: 1262038 The above error hangs xemacs 21.4.14 running on Linux xxx 2.4.22ow1np-ht #8 SMP Mon Oct 13 19:54:55 GMT 2003 i686 unknown RedHat9/Ximian Can be reproduced buy running up an xemacs 21.4.14 and a mozilla-0.9.9-7, then continually changing focus between them. I think it is todo with the exchange of active text via X property. I used to reliably reproduce it by cutting and pasting chunks of text from emacs into mozilla mail, whilst running an e.g. compile process inside emacs that was generating a lot of content. I will see if I can figure out more precise details. Cheers, Jules P.S. This is a killer - there is nothing to do but kill your xemacs after it as happened.... -- /********************************** * Jules Gosnell * Partner * Core Developers Network (Europe) **********************************/