(rmail-summary-beginning-of-message):

Obey rmail-summary-size, and make sure summary is on top
if we split a single large window.

(rmail-summary-scroll-msg-down): If message is
not visible at all, use rmail-summary-beginning-of-message.
(rmail-summary-scroll-msg-up): Likewise.

1 files changed, 17 insertions, 9 deletions

diff --git a/lisp/mail/rmailsum.el b/lisp/mail/rmailsum.el
index a23a2c7c587..9c04ef524cf 100644
--- a/lisp/mail/rmailsum.el
+++ b/lisp/mail/rmailsum.el
@@ -1072,14 +1072,13 @@ advance to the next message."
                 (rmail-summary-next-msg (or dist 1)))
             (let ((other-window-scroll-buffer rmail-buffer))
               (scroll-other-window dist)))
-        ;; This forces rmail-buffer to be sized correctly later.
-        (display-buffer rmail-buffer)
-        (setq rmail-current-message nil)))))
+        ;; If it isn't visible at all, show the beginning.
+        (rmail-summary-beginning-of-message)))))
 
 (defun rmail-summary-scroll-msg-down (&optional dist)
   "Scroll the Rmail window backward.
-If the Rmail window is displaying the beginning of a message,
-advance to the previous message."
+If the Rmail window is now displaying the beginning of a message,
+move to the previous message."
   (interactive "P")
   (if (eq dist '-)
       (rmail-summary-scroll-msg-up nil)
@@ -1099,14 +1098,23 @@ advance to the previous message."
                 (rmail-summary-previous-msg (or dist 1)))
             (let ((other-window-scroll-buffer rmail-buffer))
               (scroll-other-window-down dist)))
-        ;; This forces rmail-buffer to be sized correctly later.
-        (display-buffer rmail-buffer)
-        (setq rmail-current-message nil)))))
+        ;; If it isn't visible at all, show the beginning.
+        (rmail-summary-beginning-of-message)))))
 
 (defun rmail-summary-beginning-of-message ()
   "Show current message from the beginning."
   (interactive)
-  (pop-to-buffer rmail-buffer)
+  (if (and (one-window-p) (not pop-up-frames))
+      ;; If there is just one window, put the summary on the top.
+      (let ((buffer rmail-buffer))
+        (split-window (selected-window) rmail-summary-window-size)
+        (select-window (frame-first-window))
+        (pop-to-buffer rmail-buffer)
+        ;; If pop-to-buffer did not use that window, delete that
+        ;; window.  (This can happen if it uses another frame.)
+        (or (eq buffer (window-buffer (next-window (frame-first-window))))
+            (delete-other-windows)))
+    (pop-to-buffer rmail-buffer))
   (beginning-of-buffer)
   (pop-to-buffer rmail-summary-buffer))