Dmitry, this bug and also 13626 were both caused by your changes in
revision 111647. While the reason for the changes was to use non-Lisp
objects for some fields, several hunks in the changeset had no
relation whatsoever to that, and were highly questionable. Example:
- /* If showing the region, and mark has changed, we must redisplay
- the whole window. The assignment to this_line_start_pos prevents
- the optimization directly below this if-statement. */
- if (((!NILP (Vtransient_mark_mode)
- && !NILP (BVAR (XBUFFER (w->buffer), mark_active)))
- != !NILP (w->region_showing))
- || (!NILP (w->region_showing)
- && !EQ (w->region_showing,
- Fmarker_position (BVAR (XBUFFER (w->buffer), mark)))))
- CHARPOS (this_line_start_pos) = 0;