bug#2212: (23.0.90; excessive redisplay

[Marshall, Simon]

This still occurs in 23.0.91 and I've finally got some time to put
together a simple test case.

Replace your ~/.emacs with:

(setq inhibit-startup-screen t)
(setq default-frame-alist '((minibuffer . nil)))
(setq initial-frame-alist '((minibuffer . nil)))
(setq minibuffer-frame-alist '((reverse . t)))

And start emacs.  You will see a frame with *scratch* and a (probably
large) reverse-video minibuffer frame.

In *scratch*, type C-x d.  I see repeated redrawing of parts of the
current and minibuffer frames and their cursors, as if the focus is
being repeatedly switched between the two frames, before the Dired
prompt comes up.  (This repeated redrawing also occurs if I just switch
focus between the 2 frames by moving my mouse between them - my WM has
focus-follows-mouse.)

Type the prefix of a directory name in the current directory, eg, "ema",
and then hit TAB to complete it to, eg, "emacs-23.0.91".  Again there is
a delay before completion while focus is repeatedly switched between the
two frames.

This effect is more noticeable (and unfortunately very annoying) if
there are multiple frames open.  C-g out of Dired and type C-x 5 2 a few
times to create a stack of frames.  In one of them, type C-x d again.  I
see repeated redrawing of all of the frames, in turn, before the prompt
appears in the minibuffer.

Simon.


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