code: public final synchronized void create( HttpServletRequest request,
                                             HttpServletResponse response,
                                             ServletContext servletContext )
      {
          reinitialize( request, response, servletContext );
          initializeSharedFlowFields( request );
  
          if ( isNestable() )
          {
              // Initialize a ViewRenderer for exiting the nested page flow.  This is used (currently) as part of popup
              // window support -- when exiting a popup nested page flow, a special view renderer writes out javascript
              // that maps output values to the original window and closes the popup window.
              String vrClassName = request.getParameter( InternalConstants.RETURN_ACTION_VIEW_RENDERER_PARAM );
  
              if ( vrClassName != null )
              {
                  ViewRenderer vr =
                          ( ViewRenderer ) DiscoveryUtils.newImplementorInstance( vrClassName, ViewRenderer.class );
  
                  if ( vr != null )
                  {
                      vr.init( request );
                      PageFlowController nestingPageFlow = PageFlowUtils.getCurrentPageFlow(request, servletContext);
                      nestingPageFlow.setReturnActionViewRenderer(vr);
                  }
              }
          }
  
          super.create( request, response, servletContext );
      }
docs: This is a framework method for initializing a newly-created page flow, and should not normally be called
  directly.