@Override
 public void setAriaActivedescendantProperty(Element element, IdReference value) {
   Property.ACTIVEDESCENDANT.set(element, value);
 }
 @Override
 public String getAriaActivedescendantProperty(Element element) {
   return Property.ACTIVEDESCENDANT.get(element);
 }
 @Override
 public void removeAriaActivedescendantProperty(Element element) {
   Property.ACTIVEDESCENDANT.remove(element);
 }