Re: A GTK-only problem when making frames invisible

[martin rudalics]

> However, frame-visible-p still returns t (not
> `icon').

So we have at least two different behaviors though I'm unsure how yours
may happen.  Here I trapped it as follows: Making the frame invisible
via x_make_frame_invisible does

  /* We can't distinguish this from iconification
     just by the event that we get from the server.
     So we can't win using the usual strategy of letting
     FRAME_SAMPLE_VISIBILITY set this.  So do it by hand,
     and synchronize with the server to make sure we agree.  */
  SET_FRAME_VISIBLE (f, 0);
  SET_FRAME_ICONIFIED (f, false);

  x_sync (f);

so f->visible is zero from now on and f->iconified is false.  Next I get
an Expose event (which is a mystery to me because why should making a
frame invisible expose it) causing the execution of

          if (!FRAME_VISIBLE_P (f))
            {
              block_input ();
              SET_FRAME_VISIBLE (f, 1);
              SET_FRAME_ICONIFIED (f, false);

because "expose events must be treated like map events" as ISTR having
read somewhere.  Hence, f->visible is one from now on and f->iconified
still false.  Finally, I get the UnmapNotify event which does

          bool visible = FRAME_VISIBLE_P (f);
          /* While a frame is unmapped, display generation is
             disabled; you don't want to spend time updating a
             display that won't ever be seen.  */
          SET_FRAME_VISIBLE (f, 0);
          /* We can't distinguish, from the event, whether the window
             has become iconified or invisible.  So assume, if it
             was previously visible, than now it is iconified.
             But x_make_frame_invisible clears both
             the visible flag and the iconified flag;
             and that way, we know the window is not iconified now.  */
          if (visible || FRAME_ICONIFIED_P (f))
            {
              SET_FRAME_ICONIFIED (f, true);
              inev.ie.kind = ICONIFY_EVENT;
              XSETFRAME (inev.ie.frame_or_window, f);

so while f->visible is zero ,`visible' is true and SET_FRAME_ICONIFIED
will succeed in setting f->iconified to true.

> I don't have an earlier build from master than from 2017-01-25, which
> behaves the same.  However, with my build from emacs-25 from 2016-11-16,
> frame-visible-p returns nil.

Same here.

>>                                        And is there any difference if, as
>> a second step, you do (iconify-frame frame) instead?
>
> This does minimize the frame to the taskbar, and frame-visible-p returns
> `icon' instead of t.

As expected.

Thank your very much for testing.  Anyone else's experiences with this
would be highly interesting.  Something is fishy here.

martin