forward-line moves point horizontally when selective-display is active

[Eric Hanchrow]

[Apologies if this appears more than once]
Symptoms:

create a file named "foo.cpp" with this content (excluding the dashed lines, of 
course):
----------------------------------------
foo()
{
  if(x)
    {
      y();
    }
}
----------------------------------------

Start emacs: "emacs -Q foo.cpp"

Enable selective-display: C-u C-x $

Move point foreward three times: C-n C-n C-n

Note that the cursor is no longer in the leftmost column, but is
instead at the right end of the line with the "if".

Hit C-n twice more.  Note that the cursor doesn't move; I expected it
to immediately move down one line.

In GNU Emacs 22.0.50.1 (i686-pc-linux-gnu, X toolkit, Xaw3d scroll bars)
 of 2005-05-03 on rusty
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

Major mode: C++

Minor modes in effect:
  auto-compression-mode: t
  menu-bar-mode: t
  unify-8859-on-encoding-mode: t
  utf-translate-cjk-mode: t
  line-number-mode: t
  next-error-follow-minor-mode:  Fol
  abbrev-mode: t

Recent input:
C-x C-f / t m p / b u g . c p p RET C-u C-x $ C-n C-n 
C-n ESC x r e p l DEL o r t - e m TAB RET

Recent messages:
(./emacs -Q)
For information about the GNU Project and its goals, type C-h C-p.
Loading cc-mode...done
selective-display set to 4.
Loading emacsbug...done
-- 
Asking the Iraqi people to assume Saddam's debts
is rather like telling a man who has been shot in the head
that he has to pay for the bullet.
        -- James Surowiecki