@Override
  public void readExternal(Element element) {
    setShowDefault(JDOMExternalizer.readBoolean(element, ATTR_SHOW_DEFAULT));
    setCellSize(JDOMExternalizer.readInteger(element, ATTR_CELL_SIZE, DEFAULT_CELL_SIZE));
    setWhiteColor(JDOMExternalizerEx.readColor(element, ATTR_WHITE_COLOR, DEFAULT_WHITE_COLOR));
    setBlackColor(JDOMExternalizerEx.readColor(element, ATTR_BLACK_COLOR, DEFAULT_BLACK_COLOR));
  }
@Override
  public void readExternal(Element element)