Allow ButtonGroupWidget/SelectWidget buttons to spill on to new lines
If overflowing containing box, allow buttons in
ButtonGroupWidget/ButtonSelectWidget to break into a new line &
make sure that direction is taken care of.
(Patch is based on abandoned I54e3010eef50c1dbb1e62e2233235d12105f6c48,
without the parts that were already done in other patches.)
Co-Authored-By: jdlrobson <firstname.lastname@example.org>