code: public void onResize(final ResizeEvent event) {
  
          if ((m_selectedItem != null) && m_selectedItem.hasSubmenu()) {
  
              Scheduler.get().scheduleDeferred(new ScheduledCommand() {
  
                  /**
                   * @see com.google.gwt.user.client.Command#execute()
                   */
                  public void execute() {
  
                      getSelectedItem().getSubMenu().setSubMenuPosition(getSelectedItem());
                      getSelectedItem().getSubMenu().onResize(event);
                  }
              });
          }
      }
docs: If the browser's window is resized this method rearranges the sub menus of the selected item.<p>
  
  @see com.google.gwt.event.logical.shared.ResizeHandler#onResize(com.google.gwt.event.logical.shared.ResizeEvent)