On Fri, Dec 15, 2017 at 11:10 AM, Eli Zaretskii <eliz@gnu.org> wrote:

> > From: Robert Weiner <rsw@gnu.org>
> > Date: Fri, 15 Dec 2017 10:53:59 -0500
> > Cc: emacs-devel <emacs-devel@gnu.org>
> >
> > Although from the function doc strings, it seems a force-window-update
> > followed by a (sit-for 0) should force redisplay of the chosen window,
> it did
> > not (see the test2 function in the prior message).  Is that a bug?
>
> How do you know Emacs didn't redisplay the window?  "Force redisplay"
> doesn't necessarily mean you will see on display what you think you
> should see, it just means Emacs will consider that window for
> redisplay.  Whether that causes Emacs to show what you think it should
> is another matter entirely: the display engine has its own ideas what
> part(s) of the window need to be redrawn, if any.
>
> I actually don't understand the idea of your test2 function: can you
> tell what you intended to see happen, and why?
>

​The problem was that I would set-window-buffer in the new frame
to a different buffer and that buffer would not display when
the new frame was brought frontmost and displayed temporarily
with a sleep-for delay.  Calling force-window-update had no
effect but calling (redisplay t) resolved it.

Bob