And,,, "leader" and "trailer" only work together if "both" is selected for text "dual view" of units. (??) And,, when "both" is selected the trailer and leader only show in front or behind the "secondary units" and no trailer and leader for primary sitting innocently above secondary. But only if the dimension was first placed with "secondary only" selection then changed. Seems like some code got stepped on in the writing process and never corrected.