This bug report will be sent to the XEmacs Development Team, not to your local site managers!! Please write in English, because the XEmacs maintainers do not have translators to read other languages for them. In XEmacs 21.2 (beta26) "Millenium" [Lucid] (hppa1.1-hp-hpux11.00, Mule) of Sat Jan 1 2000 on tmbbwmt configured using `configure hppa1.1-hp-hpux11.00 --dynamic=no --prefix=/usr/local/xemacs --with-x --with-dialogs=motif --with-xface=yes --with-tty=yes '--x-includes=/usr/include/Motif2.1 -I/usr/include/X11R6' '--x-libraries=/usr/lib/Motif1.2_R6 -L/usr/lib/X11R6' --with-database=dbm --with-pop --mail-locking=lockf '--site-includes=/usr/contrib/include -I/usr/local/include' --error-checking=none --extra-verbose '--site-libraries=/usr/contrib/lib -L/usr/local/lib' --with-sound=no --with-xmu --with-mule=yes --with-cde=yes --with-tooltalk=yes --with-gcc=no --package-path=/opt/src/packages '--cflags=+DS2.0 +DA1.1 +O3 +ESlit +Oloop_transform +Odataprefetch +Onolimit +Oprocelim +Olibcalls +Ofastaccess'' While pressing a button in the Ediff window (toolbar enabled) I got Fatal error: assertion failed, file redisplay.c, line 7516, abort() Fatal error (6). Your files have been auto-saved. Lisp backtrace follows: event-window(#<motion-event 45, 9>) # bind (frame event) default-mouse-motion-handler(#<motion-event 45, 9>) # (condition-case ... . error) # (catch top-level ...)