The Face Set visibility operator was using the last active Face Set
updated by the paint cursor, so when the paint cursor is not used (when
using a filter or a transform tool), the active Face Set was not updating
and it was hidding the wrong Face Set based on the last cursor position
with a brush tool active. Now the Face Set Visitility operator has an
invoke callback wich forces a active vertex and face set update
regardless of the active tool, so it should always work correctly.
Reviewed By: sergey
Differential Revision: https://developer.blender.org/D8580
762daacbc7