The code in apply_horiz_layout systematically does `set_position`
then `set_size`, so for new windows there is an invalid call.
For old windows there are two calls when only one is needed,
with the current code set_position could not send any surface
configure without impact, but in the future it might be needed?
Native wayland surfaces do not need to know where they are (the
set_position handled only updates the sway internal view variable),
why does X11 window need that?
