In the GTK style the scroll bar likes to be outside of the scroll area
frame. Like with the completion widget, we put the visible frame
explicitly outside of the scroll bar.
Reviewed-by: Jens Bache-Wiig
It looks wrong when a shadow is added, which a lot of window managers do
these days. Whether is looks better when no shadow is added by the
window manager is debatable.
Reviewed-by: Jens Bache-Wiig
