private void initUI() {
    if (myPanel != null) {
      return;
    }
    myPanel = new JPanel(new BorderLayout());
    ComponentUtil
      .putClientProperty(myPanel, UIUtil.NOT_IN_HIERARCHY_COMPONENTS, (Iterable<? extends Component>)(Iterable<JComponent>)() -> {
        if (myContentManager == null || myContentManager.getContentCount() == 0) {
          return Collections.emptyIterator();
        }
        return JBIterable.of(myContentManager.getContents())
          .map(content -> {
            JComponent component = content.getComponent();
            return myPanel != component.getParent() ? component : null;
          })
          .filter(Conditions.notNull())
          .iterator();
      });
  }
private void initUI()