bug#44180: 28.0.50; Emacs frames won't redisplay unless resized

[martin rudalics]

> The problem is that switching focus between windows (frames) does not
> update which window is "live". The most-recently created, or
> most-recently resized, window is always the live one. If I switch focus
> to one of the other frames, it doesn't update, and I need to move it
> around somehow in order to make it live. Then the other frames go dead.
>
> Before the breakage, it's possible that the non-visible frames were not
> updated while they remained invisible, and I simply never knew because
> I couldn't see them. Now they stay un-updated until I manipulate the
> size of the window somehow.

Do you get the corresponding focus events (whatever they are now) when
you make another frame the fullscreen one?  If so, we should probably
redraw the frame in that case.

martin