Re: master cc29fab3a6: Redisplay "invisible" frames that are actually visible on modern X

[Eli Zaretskii <eliz@gnu.org>]

> From: Stefan Monnier <monnier@iro.umontreal.ca>
> Cc: emacs-devel@gnu.org
> Date: Mon, 26 Dec 2022 09:04:26 -0500
> 
> > +** Emacs will now redisplay frames that are made visible by a compositor.
> > +This means even if `frame-visible-p' returns nil or `icon', the frame
> > +will be redisplayed if it is being displayed to the user by the
> > +compositing manager, which can happenas part of a preview for
> > +iconified windows.
> 
> FWIW, while this sounds about right for `icon`ified frames, for those
> frames that are marked as actually invisible, I think we should try and
> keep them as invisible as possible.

I'm not sure I agree.  I believe this could belong to some new GUI
ideas (all of which are invariably copy-cat'ed from MS-Windows ;-),
whereby you have a means of showing a small-but-still-readable image
of an otherwise invisible frame, e.g., by hovering the mouse above
some desktop icon or widget.  If that is the intent, then this is not
a bug, but a feature of those WMs, and an important/boastable feature
at that.

> Keeping the preview's appearance up-to-date is wasted efforts in
> this respect.

Not in the eyes of those beholders, it isn't.

But I do think this should be an optional feature (we could argue
later about the defaults).  In an Emacs session with a dozen
invisible/iconified frames, updating those frames without the user's
say-so could be a misfeature and a performance hit.