@Override
  protected void addImpl(Component component, Object name, int index) {
    Key<Component> key = LEADING.equals(name) ? DefaultScrollBarUI.LEADING : TRAILING.equals(name) ? DefaultScrollBarUI.TRAILING : null;
    if (key != null) {
      Component old = ClientProperty.get(this, key);
      ClientProperty.put(this, key, component);
      if (old != null) {
        remove(old);
      }
    }
    super.addImpl(component, name, index);
  }
@Override
  protected void addImpl(Component component, Object name, int index)