code: protected void installNotificationWidget() {
  
          if (m_notificationWidgetInstalled) {
              return;
          }
          // remember current notification widget
          m_parentNotificationWidget = CmsNotification.get().getWidget();
          // create our own notification overlay
          if (m_ownNotificationWidget == null) {
              m_ownNotificationWidget = createDialogNotificationWidget();
          }
          add(m_ownNotificationWidget);
          CmsNotification.get().setWidget(m_ownNotificationWidget);
          m_notificationWidgetInstalled = true;
      }
docs: Sets the notification widget.<p>