C-x 4 b RET does not restores wrong other window

["Ture Pålsson" <ture@lysator.liu.se>]

In GNU Emacs 21.2.1 (i686-pc-linux-gnu, X toolkit)
 of 2002-03-20 on paddington
configured using `configure  --prefix=/sw/emacs/21.2'
Important settings:
  value of $LC_ALL: nil
  value of $LC_COLLATE: nil
  value of $LC_CTYPE: sv_SE
  value of $LC_MESSAGES: nil
  value of $LC_MONETARY: nil
  value of $LC_NUMERIC: nil
  value of $LC_TIME: nil
  value of $LANG: C
  locale-coding-system: iso-latin-1
  default-enable-multibyte-characters: t

Symptoms and how to reproduce:

1. Start emacs with emacs -q --no-site-file

2. Type C-x 2 C-x 2. This should give you three windows, all showing
   the *scratch* buffer, with the cursor in the topmost one.

3. Type C-h f c o n s RET. This gives you the help text for 'cons' in
   the middle window, and the text "Type C-x 4 b RET to restore other
   window.  C-M-v to scroll the help." in the echo area. The cursor is
   still in the topmost window.

4. Type C-x 4 b RET. I expected this to switch the middle window from
   the *Help* buffer back to *scratch*, but instead it switched the
   bottom window from *scratch* to *Messages*.