void selectEdge(JPolygon toSelect, PlanEdge edge) {
   clear();
   selectedEdge = edge;
   selectedElementPolygon = toSelect;
   toSelect.setSelectedEdge(edge);
   super.setChanged();
   super.notifyObservers(toSelect);
 }
 @Override
 public void clear() {
   clearEdgeInternal();
   super.clear();
 }
 @Override
 public void select(JPolygon toSelect) {
   clearEdgeInternal();
   super.select(toSelect);
 }