public void setGridLine(GridLine gl) {
   if (gl == null) {
     gridLines.removeAll();
   } else {
     gridLines.add(gl);
   }
 }
  /** @throws IllegalArgumentException if DataSetKind is not Multi */
  public void addFillArea(FillArea fa) {

    if (!fa.getDataSetKind().equals(FillArea.DataSetKind.Multi))
      throw new IllegalArgumentException("only FillArea.DataSetKind.Multi allowed");

    fillAreas.add(fa);
  }
 public FillArea removeFillArea(int index) {
   return fillAreas.remove(index);
 }
 public void removeAllFillAreas() {
   fillAreas.removeAll();
 }
 public List<FillArea> getFillAreas() {
   return fillAreas.getList();
 }
 public boolean removeShapeMarker(ShapeMarker sm) {
   return shapeMarker.remove(sm);
 }
 public ShapeMarker removeShapeMarker(int index) {
   return shapeMarker.remove(index);
 }
 public void removeGridLine() {
   gridLines.removeAll();
 }
 public List<ShapeMarker> getShapeMarkers() {
   return shapeMarker.getList();
 }
 public boolean removeRangeMarker(RangeMarker rm) {
   return rangeMarker.remove(rm);
 }
 public RangeMarker removeRangeMarker(int index) {
   return rangeMarker.remove(index);
 }
 public void removeAllRangeMarkers() {
   rangeMarker.removeAll();
 }
 public List<RangeMarker> getRangeMarkers() {
   return rangeMarker.getList();
 }
 public void addRangeMarker(RangeMarker rm) {
   rangeMarker.add(rm);
 }
 public boolean removeFillArea(FillArea fa) {
   return fillAreas.remove(fa);
 }
 public void removeChartTitle() {
   title.removeAll();
 }
 public void removeAllShapeMarkers() {
   shapeMarker.removeAll();
 }