bug#61667: 29.0.60; Failure to redisplay

[Po Lu via "Bug reports for GNU Emacs, the Swiss army knife of text editors" <bug-gnu-emacs@gnu.org>]

Gregory Heytings <gregory@heytings.org> writes:

> Thanks!  After seeing this, I'm now convinced that the problem is not
> a GNOME one, for two reasons:
>
> 1.  The effect of (insert "!") (redisplay) is immediately visible on
> screen.  Why would GNOME treat the effect of changing the buffer from
> *scratch* to xassociations.rb differently?

If you insert "!", the frame title does not change, right?
Everything points to this being a bug somewhere in Mutter: how damage to
surrounding windows (including obscured ones) prevents it from showing
up, and how it doesn't show up in an undecorated frame.

Dimitry, do you see any delay between the change in the frame title and
when ``Test 2'' becomes visible?  With and without double buffering, and
with and without `undecorated' set to `t'?

  (progn
    (sleep-for 1)
    (setq frame-title-format icon-title-format)
    (insert "Test 1")
    (force-mode-line-update)
    (redisplay)
    (sleep-for 1)
    (setq frame-title-format "test title")
    (insert "Test 2")
    (force-mode-line-update)
    (redisplay))