bug#2282: Bug#2282: rmail-summary splits frame into three parts

[martin rudalics]

> I'm tempted to just replace all pop-to-buffers in rmail*.el with
>
> (defun rmail-pop-to-buffer (buffer-or-name &optional other-window norecord)
>   (let (split-width-threshold)
>     (pop-to-buffer buffer-or-name other-window norecord)))

I suppose the following code in `rmail-new-summary' is responsible for
the behavior described earlier.

      (if (and (one-window-p)
               pop-up-windows
               (not pop-up-frames))
          ;; If there is just one window, put the summary on the top.
          (progn
            (split-window (selected-window) rmail-summary-window-size)
            (select-window (next-window (frame-first-window)))
            (pop-to-buffer rmail-summary-buffer)
            ;; If pop-to-buffer did not use that window, delete that
            ;; window.  (This can happen if it uses another frame.)
            (if (not (eq rmail-summary-buffer
                         (window-buffer (frame-first-window))))
                (delete-other-windows)))
        (pop-to-buffer rmail-summary-buffer))

What is that code supposed to do what a simple `pop-to-buffer' cannot
accomplish?  If it's to display the summary on top of the frame, then
splitting horizontally obviously won't make sense here.

martin