RenderUtils.invalidateViewState();
    public ActionForward chooseLesson(ActionMapping mapping, ActionForm form, HttpServletRequest request,	    HttpServletResponse response) {	final IViewState viewState = RenderUtils.getViewState();	SummariesManagementBean bean = (SummariesManagementBean) viewState.getMetaObject().getObject();		bean.setSummaryDate(null);	return goToSummaryManagementPage(mapping, request, (DynaActionForm)form, bean);    }