undo moves point when it shouldn't

[John H Palmieri]

In GNU Emacs 21.1.1 (alphaev5-dec-osf5.0, X toolkit)
 of 2001-10-22 on goedel1.math.washington.edu
configured using `configure  --prefix=/scratch/palmieri'
Important settings:
  value of $LC_ALL: nil
  value of $LC_COLLATE: nil
  value of $LC_CTYPE: nil
  value of $LC_MESSAGES: nil
  value of $LC_MONETARY: nil
  value of $LC_NUMERIC: nil
  value of $LC_TIME: nil
  value of $LANG: nil
  locale-coding-system: nil
  default-enable-multibyte-characters: t

Please describe exactly what actions triggered the bug
and the precise symptoms of the bug:


I don't know if this is a bug or not.  If not, consider it a feature
request.

I started with 'emacs -q'.  I found a file "bozo.el" which has some
lisp code in it.  I defined a region by setting the mark and moving,
then ran 'M-x comment-region'.  Then I hit 'C-x u'.  Here's the
problem: the point was changed -- the point was now the mark.
(Actually, it seems that in this situation, 'C-x u' moves the point to
the beginning of the region, whether that was the mark or the point.
Or maybe it moves to the first place in the region which was changed.)

As I said, I don't know if this is a bug, but I think this is bad; it
would be better if undo didn't change the point this way.  I think a
better thing to do would be to restore the point to where it was when
comment-region was run.

For example, if I want to comment out 500 lines, if I accidentally run
comment-region and comment out 505 lines, it should be easy for me to
undo this and comment out the correct 500 -- running undo shouldn't
make emacs forget the region, forcing me to scroll hundreds of lines
to find the right spot.

-- 
J. H. Palmieri
Dept of Mathematics, Box 354350    mailto:palmieri@math.washington.edu
University of Washington           http://www.math.washington.edu/~palmieri/
Seattle, WA 98195-4350