bug#31968: 26.1.50; Allow to hide title bar on maximize (gtk/gnome/csd)

[martin rudalics]

> Under Cinnamon it worked without flickering.

Thanks.  But please post your code here so we know what we are
discussing.

> There is just a minor
> problem that could be pointing to a bug elsewhere in emacs. Cinnamon
> implements a progression of tiles layouts, for instance starting from
> a normal sized window (i) you press Super-Up and the window is tiled
> to the top half of the screen, (ii) you then press Super-Up again and
> the window is maximized, (iii) finally you press Super-Down and the
> window returns to top half tile mode. In general only fully maximized
> windows (ii) gets undecorated, as intended, but when transitioning
> from fully maximized to top half tiled (ii->iii) emacs still sees the
> maximized state in the fullscreen frame parameter and fails to
> undecorate the window. Nevertheless the client state in (ii) is:
>
> ~:: xprop | grep _NET_WM_STATE
> _NET_WM_STATE(ATOM) = _NET_WM_STATE_MAXIMIZED_VERT, _NET_WM_STATE_TILED
>
> The problem seems to be in the reported frame parameters, not in
> Jonathan's hook.

get_current_wm_state in xterm.c has this

      else if (a == dpyinfo->Xatom_net_wm_state_maximized_vert)
        {
          if (*size_state == FULLSCREEN_WIDTH)
            *size_state = FULLSCREEN_MAXIMIZED;
          else
            *size_state = FULLSCREEN_HEIGHT;
        }

Could you try setting a GDB breakpoint at the

          if (*size_state == FULLSCREEN_WIDTH)

line and see if it ever gets executed during (ii->iii).

Thanks for trying, martin