code: protected void pushIdScope()
      {
          if (_idScope != null) {
              HttpServletRequest req = (HttpServletRequest) pageContext.getRequest();
              ArrayList/*<String>*/ list = (ArrayList/*<String>*/) RequestUtils.getOuterAttribute(req,SCOPE_ID);
              if (list == null) {
                  list = new ArrayList/*<String>*/();
                  RequestUtils.setOuterAttribute(req,SCOPE_ID,list);
              }
              list.add(_idScope);
  
          }
      }
docs: ///////////////////////////////// Protected Support ////////////////////////////////////