public void unrelateAcrossR19From(Shape_c target, boolean notifyChanges) {
   if (target != null) {
     target.unrelateAcrossR19From(this, notifyChanges);
   }
 }
 public void unrelateAcrossR19From(Shape_c target) {
   if (target != null) {
     target.unrelateAcrossR19From(this, true);
   }
 }