public function insert($widget, $label)
 {
     $event = new GtkEventBox();
     $event->set_visible_window(FALSE);
     $event->add($label);
     $this->notebook->insert_page($container = new GtkEventBox(), $event);
     $container->add($widget);
     $label->show();
     $this->containers[] = $container;
     $this->labels[] = $label;
     $this->abas[] = $widget;
 }