bug#5482: frame-invisible-p reports nil for iconified frames on w32

[Eli Zaretskii <eliz@gnu.org>]

> Date: Mon, 27 Jun 2016 08:22:06 +0200
> From: martin rudalics <rudalics@gmx.at>
> CC: ahyatt@gmail.com, lennart.borgman@gmail.com, 5482@debbugs.gnu.org
> 
>  > I could perhaps agree that iconify-frame should have undone the effect
>  > of make-frame-invisible in this use case, though.
> 
> I see no problems with
> 
> (progn
>    (setq my-frame (make-frame))
>    (make-frame-invisible my-frame)
>    (sit-for 1)
>    (iconify-frame my-frame)
>    (sit-for 1)
>    (frame-visible-p my-frame))
> 
> Or what did you have in mind?

On Windows 7, calling iconify-frame doesn't cause the frame to show
when the mouse pointer hovers above the Emacs icon on the task bar, as
if the frame is still invisible.  No such problem on XP, though.