untabify does not preserv bookmarks

[M Frasson]

Symptoms:

Hi.

If I set a bookmark (with C-x r m) in a buffer that has tabs, I select
a region (with lots of tabs) and untabify if (with C-x untabify) and I
go to mark, the point is often moved.

I saw this behaviour in emacs-lisp mode, if it matters.

In GNU Emacs 21.3.50.1 (i386-mingw-nt5.1.2600)
 of 2004-07-09 on FARIBA
configured using `configure --with-gcc (3.2) --cflags 
-I/home/fariba_soleymani/dev/include'

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: 1033
  locale-coding-system: cp1252
  default-enable-multibyte-characters: t

Major mode: Emacs-Lisp

Minor modes in effect:
  file-name-shadow-mode: t
  delete-selection-mode: t
  pc-selection-mode: t
  tool-bar-mode: t
  encoded-kbd-mode: t
  mouse-wheel-mode: t
  menu-bar-mode: t
  global-font-lock-mode: t
  font-lock-mode: t
  unify-8859-on-encoding-mode: t
  utf-translate-cjk-mode: t
  column-number-mode: t
  line-number-mode: t
  transient-mark-mode: t

Recent input:
<left> <left> C-x r m <return> <home> <up> <S-down> 
<S-down> <S-down> M-x u n t a b i f y <return> C-x 
r b <return> <help-echo> <help-echo> <help-echo> <wheel-up> 
<home> <S-end> <delete> <delete> <tab> <left> <left> 
<left> <left> <left> <left> <left> <left> <left> <left> 
<left> <left> <left> <left> <left> <left> <left> <left> 
<left> <left> <left> <left> <left> <left> <left> <left> 
<left> <left> <left> <left> <left> <left> <left> <right> 
<right> <right> <right> <right> <right> <right> <right> 
<right> <right> <right> <right> <help-echo> <help-echo> 
<help-echo> <help-echo> <help-echo> <help-echo> <help-echo> 
<help-echo> <help-echo> <help-echo> C-x C-s <help-echo> 
<help-echo> <help-echo> <help-echo> <help-echo> <help-echo> 
<menu-bar> <help-menu> <report-emacs-bug>

Recent messages:
Loading tabify...done
Loading help-fns...done
Type C-x 1 to remove help window.  C-M-v to scroll the help.
Mark set
Auto-saving...done
Mark set [2 times]
Auto-saving...done
Saving file f:/auctb/toolbarx.el...
Wrote f:/auctb/toolbarx.el
Loading emacsbug...done