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