code: public void setTransparentAreasEnabled(final boolean TRANSPARENT_AREAS_ENABLED) {
          transparentAreasEnabled = TRANSPARENT_AREAS_ENABLED;
          init(getInnerBounds().width, getInnerBounds().height);
          repaint(getInnerBounds());
      }
docs: Enables / disables the usage of a transparent color for filling areas
  @param TRANSPARENT_AREAS_ENABLED