anchor.diff:  
     PRIVATE SECTION.
   
  +    TYPES: BEGIN OF ty_page_stack,
  +             page     TYPE REF TO lif_gui_page,
  +             bookmark TYPE abap_bool,
  +           END OF ty_page_stack.
  +
       DATA: mi_cur_page    TYPE REF TO lif_gui_page,
  -          mt_stack       TYPE TABLE OF REF TO lif_gui_page,
  +          mt_stack       TYPE TABLE OF ty_page_stack,
             mt_assets      TYPE tt_w3urls,
             mo_router      TYPE REF TO lcl_gui_router,
             mo_user        TYPE REF TO lcl_persistence_user,
  
positive.code:             render( ).
            WHEN gc_event_state-new_page.
              call_page( li_page ).
            WHEN gc_event_state-go_back.
              back( ).
            WHEN gc_event_state-no_more_act.
              " Do nothing, handling completed
            WHEN OTHERS.
  
negative.code:       RAISING lcx_exception.
  
      METHODS back
        IMPORTING iv_to_bookmark TYPE abap_bool DEFAULT abap_false
        RETURNING VALUE(rv_exit) TYPE xfeld
        RAISING   lcx_exception.
  
      METHODS call_page
        IMPORTING ii_page          TYPE REF TO lif_gui_page
                  iv_with_bookmark TYPE abap_bool DEFAULT abap_false
        RAISING   lcx_exception.
  
      METHODS set_page
  