The Layer Style dialog's OK and Cancel came after the style list and
the style's controls in one scroll area, and at its usual size they
were laid out past the dialog's bottom edge: clipped, and a click on
them did nothing until the dialog was scrolled.
The dialog now uses above_footer: OK and Cancel sit at its bottom right
and the list and the controls scroll above them, also at 200 % UI
Scale.
Test: layer_style_buttons_stay_in_view (both buttons painted whole and
clicked, at 100 % and 200 %; fails before: Cancel isn't painted).
tylerjenningsw
bf911d18bc