Disable fix from [0] unless LIBDECOR is used.
This caused:
- KDE 6.0.2 to fail to start full-screen.
- RIVERWM to show a blank preferences.
- HYPRLAND to assert with a negative window height
when starting full-screen.
Also replace flush & dispatch with a round-trip which fixes an error
on GNOME with non maximized/full-screen windows not showing any contents
on startup until a redraw was triggered.
[0]: 7371b11bb5
3f7742f65d