mode-line keymap properties issue when window is split horizontally

[David PONCE <david.ponce@wanadoo.fr>]

Hi,

When a window is split horizontally, keymap properties in the
mode-line (or header-line) are ignored on the window on the right.

A simple scenario to reproduce the problem:

emacs -q -no-site-file
C-x 3

On the left window:

mouse-1/mouse-3 on the buffer name in the mode line correctly switch
to the previous/next buffer.

On the right window:

mouse-1 on the buffer name in the mode line does nothing.
mouse-3 calls `mouse-delete-window' (that is the global binding of
[<mode-line> <mouse-3>]).

The same scenario works with Emacs 21.3.1.

Sincerely,
David

In GNU Emacs 21.3.50.1 (i386-mingw-nt4.0.1381)
 of 2003-06-02 on EBAT311
configured using `configure --with-gcc (3.2)'

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: ENU
  locale-coding-system: iso-latin-1
  default-enable-multibyte-characters: t