New symptom and code

["David Vanderschel" <DJV4@Austin.RR.com>]

I should have mentioned that I am using the minibuffer
primarily so that I can get a temporary multi-line
display.  Otherwise, I could have used message.  I am
not letting the user edit in the minibuffer.  I am
just showing him some data.  The single character he
types is treated by my program as a command, which
then modifies the display.

I just encountered another very weird symptom.  I had
two frames open.  I invoked the function as usual in a
frame with a single window - the only window in which
the function was bound to a key.  Its minibuffer grew
in the manner I had intended.  However, the string
which was supposed to go in the minibuffer wound up in
the minibuffer of the other frame.  This makes no
sense.  There is no concept of multiple minibuffers in
the my code.

Maybe I should just show my current iteration of the
code:

(defun Hube-config-dialogue (msg valid-chars)
"Show (possibly multi-line) MSG in minibuffer; read and return an input char.
Return 0 if input character is not among those in list VALID-CHARS."
  (interactive)
  (save-selected-window
    (select-window (minibuffer-window)) (erase-buffer) (insert msg)
    (let ((auto-save-interval 600) (echo-keystrokes 0) (enlargement 0))
      (while (not (pos-visible-in-window-p)) (enlarge-window 1) (incf
enlargement))
      (let* ((s (read-key-sequence nil)) (c (elt s 0)))
        (erase-buffer) (shrink-window enlargement) (if (member c valid-chars) c
0)))))

What do I need to understand to get this right?

Regards,
  David V.