commit: Fix window-configuration problem.

[Stephen J. Turnbull]

Michael Sperber writes in a commit notice on XEmacs Patches:

Hg log:

 > Fix window-configuration problem.

This greatly improves, maybe eliminates, the anomolies I've been
seeing in VM summary buffers with random point movement.  This is an
X-enabled build but in a TTY over ssh.  Can other VM testers update to
tip of "xemacs" (or if you're following "xemacs-beta", it should be
there in a day or two -- my build was clean FWIW) and report if you
see an improvement, or continuing anomolies?

In a quick test, it does *not* fix issue303 for me (but I have not
done a full rebuild with the patch yet, just a "make").

Mike, Jerry, the following issues in the tracker may be related.

issue134, Infinite loop in ecb, apparently in current-window-configuration
issue227, Infinite loop in ecb, apparently in current-window-configuration
issue303, [Bug: 21.5-b28] Bogus motion of modeline

I've assigned them to Mike but 134 and 227 might better be assigned to
Jerry and/or closed if they've been fixed.  If 134 and 227 are the
same issue, please close one as superseded by the other.  I think 227
has more information, so 134 is the better candidate for that.