When entering scultp mode the visibility from the Face Sets is copied to the base mesh. This steps was considering that if a vertex belongs to a face with a visibible Face Set ID, it should be visible. As loose geometry may not have any faces, those vertex were set to hidden. Now this function check if a vertex visibility should be modified by the face sets (by checking the loops), avoiding modifying the visibility of loose geometry unintentionally. Reviewed By: sergey Maniphest Tasks: T80771 Differential Revision: https://developer.blender.org/D8899