Crash (assertion failed) in 21.2.44

Hi, I have reported this bug once already, but apparentlyy nobody took notice. So here it is again. This happens on a fairly regular basis on my system. Last time it happened twice in a row after exactly same actions (copy a line from one buffer, switch to another, go to the top and 2 lines down, paste - boom), but unfortunately I could not repro it after that. My feeling is that the bug occurs when I do things really fast (which would explain why I couldn't repro it). The assertion is below. I have no idea what the code that causes it does, but would be willing to help somebody who knows - e.g. I can add some checking code to the problematic place etc. In any case, this bug is as good a showstopper as any for a "release" so at least some attention by one of XEmacs' core writers is I think justified. LUCY:~$xemacs & LUCY:~$Fatal error: assertion failed, file /usr/local/src/xemacs-21.2/src/insdel.c, line 1115, ( retval) >= BI_BUF_BEG (buf) && retval <= BI_BUF_Z (buf) [1]+ Exit 1 xemacs XEmacs 21.2 (beta44) "Thalia" [Lucid] (i686-pc-cygwin) of Tue Feb 13 2001 on LUCY LUCY:~$uname -a CYGWIN_NT-5.0 LUCY 1.1.8(0.34/3/2) 2001-01-31 10:08 i686 unknown -- Cheers, -Dima.