root = new HBox();
root.pointerTransparentProperty().set(true);
rootPanel.getChildren().add(root);
this.onChildrenChangedEvent().addListener(onChildrenChangedEventListener);
rootPanel.onClickEvent().addListener(new IEventListener<ClickEventArgs>() {
@Override
public void onFired(ClickEventArgs args) {
fireItemClickedEvent(SimpleTreeViewItem.this);
}