code: void clearNotifications() {
  
          if (m_parentNotificationWidget != null) {
              // restore the previous notification widget
              CmsNotification.get().setWidget(m_parentNotificationWidget);
          }
          if (m_ownNotificationWidget != null) {
              // remove the overlay notification widget
              remove(m_ownNotificationWidget);
          }
      }
docs: Resets the notification to the parent notification widget and detaches the own notification widget.<p>