public boolean removeFillArea(FillArea fa) {
   return fillAreas.remove(fa);
 }
 public FillArea removeFillArea(int index) {
   return fillAreas.remove(index);
 }
 public boolean removeShapeMarker(ShapeMarker sm) {
   return shapeMarker.remove(sm);
 }
 public ShapeMarker removeShapeMarker(int index) {
   return shapeMarker.remove(index);
 }
 public boolean removeRangeMarker(RangeMarker rm) {
   return rangeMarker.remove(rm);
 }
 public RangeMarker removeRangeMarker(int index) {
   return rangeMarker.remove(index);
 }