private void addComboBoxItems() {
   int maxColorSchemeSize = -1;
   for (Iterator i = ColorScheme.rangeColorSchemeNames().iterator(); i.hasNext(); ) {
     String rangeColorSchemeName = (String) i.next();
     maxColorSchemeSize =
         Math.max(maxColorSchemeSize, ColorScheme.create(rangeColorSchemeName).getColors().size());
   }
   for (int i = 3; i <= maxColorSchemeSize; i++) {
     comboBoxModel.addElement(new Integer(i));
   }
 }