Re: Emacs-26.0.91: switch-to-buffer-other-window runs too slowly (about 0.1s)

[martin rudalics]

> For the purposes of this discussion, I'll settle with a subset of my
> question, viz.: when FRAME_VISIBLE_P returns non-zero, is it possible
> that the frame is in fact not visible?
>
> If a non-zero value of FRAME_VISIBLE_P reliably tells us that the
> frame is visible, then we can avoid waiting for MapNotify when
> FRAME_VISIBLE_P returns non-zero at entry into x_make_frame_visible.
> (This is what the original code circa Emacs 21 did, AFAIR.)

I mentioned my concerns because I obviously had the same idea.  My
answer is simple: I think it's possible that FRAME_VISIBLE_P lies and
we should disregard that.  If it lies, it's a good occasion to find
out and think of a fix for Emacs 27.

And obviously I have no good ideas for Emacs 26.

martin