bug#49997: 27.2; idle-time reset when switching desktop-page

[Eli Zaretskii <eliz@gnu.org>]

> From: Peter Münster <pm@a16n.net>
> Cc: larsi@gnus.org,  49997@debbugs.gnu.org
> Date: Mon, 16 Aug 2021 19:10:37 +0200
> 
> >> But IMHO the idle time should not be reset to 0, when the window moves.
> >
> > Not even when the user moves the window? why not?
> 
> Because that's my understanding of idleness: when nothing is done inside
> of Emacs, the idle timer should keep running. When the window is just
> moved to another place, there is no real input.
> Same with my kid: when he sleeps, he keeps sleeping even when I carry him
> to another bedroom... ;)

The only definition of "idleness" we can use in Emacs is that Emacs is
not processing any input events.  This is fundamental.  I don't know
how to define "nothing is done inside Emacs" otherwise.  If taken
literally, this is something that never happens, because the main loop
in Emacs always runs, and always "does things".

> Anyway: when the user moves the window, there will be certainly also an
> focus-in event, that can trigger the reset of the idle timer.

So focus-in events are different for some reason?  I guess we will
have to agree to disagree.

That said, we could perhaps provide user control on what constitutes
an event that can stop the idleness.  Some sort of list of events that
are disregarded for this purpose, maybe.  Patches welcome.