Ah, %$#＠%!#$. There is one ! too many in this patch. Here is what I meant Index: redisplay.c =================================================================== RCS file: /usr/CVSroot/XEmacs/xemacs-20/src/redisplay.c,v retrieving revision 1.57 diff -u -u -r1.57 redisplay.c --- redisplay.c 1999/05/12 14:29:13 1.57 +++ redisplay.c 1999/08/12 19:37:53 ＠＠ -6245,6 +6245,19 ＠＠ lsc.end = dl->end_bufpos; lsc.height = dl->ascent + dl->descent; + { + struct buffer *buf = XBUFFER(w->buffer); + /* Paranaoid line start cache check */ + if (! (lsc.start <= BUF_BEGV(buf) || + BUF_FETCH_CHAR(buf,lsc.start - 1) == (Emchar) '\n')) + { + fprintf(stderr,"Wrong stuff in line start cache!\n" + "Supposedly begins at: %10s", + (char *)BUF_BYTE_ADDRESS(buf,lsc.start)); + assert(0); + } + } + Dynarr_add (internal_cache, lsc); } } However there is no need to run that. For me it crashes displaying the splash screen. The reason: a wrapped line. (Sorry if this gets technical) The problem is that \ when a line is wrap \ ped like this Then there are 3 display lines and the second 2 don't actually start at a new line in the buffer, just in the display. Previous line_start_cache rediplay crashes have all been of the type where code actually assumed that the line_start_cache actually contained lines starting at "\n", and we have fixed the triggers for that. It seems now that we better check these assumptions. i'm too tired now to have a real look. Gunnar Do you remember where that problem occured, was it also at asssert(cur_elt>=0)? Jan BTW Hamish, does the reproduction recipe at the end of http://www.xemacs.org/list-archives/xemacs-beta/9903/msg00475.html "work" for you?