bug#9831: narrowing the bug down

[Mark Lillibridge]

I have also run into this bug on Emacs 23.3.  It is quite annoying.

So far I have determined that the bug is caused by the following lines:

rmailout.el:386:
    ;; FIXME should re-use existing windows.
    (if (rmail-summary-exists)
        (rmail-select-summary (rmail-update-summary)))

Commenting out those two lines makes the bug go away.

- Mark