anchor.diff:              render( ).
             WHEN gc_event_state-new_page.
               call_page( li_page ).
  +          WHEN gc_event_state-new_page_w_bookmark.
  +            call_page( ii_page = li_page iv_with_bookmark = abap_true ).
             WHEN gc_event_state-go_back.
               back( ).
  +          WHEN gc_event_state-go_back_to_bookmark.
  +            back( iv_to_bookmark = abap_true ).
             WHEN gc_event_state-no_more_act.
               " Do nothing, handling completed
             WHEN OTHERS.
  
positive.code: 
    PRIVATE SECTION.
  
      DATA: mi_cur_page    TYPE REF TO lif_gui_page,
            mt_stack       TYPE TABLE OF REF TO lif_gui_page,
            mt_assets      TYPE tt_w3urls,
            mo_router      TYPE REF TO lcl_gui_router,
            mo_user        TYPE REF TO lcl_persistence_user,
  
negative.code: 
    METHOD back.
  
      DATA: lv_index TYPE i,
            ls_stack TYPE ty_page_stack.
  
      lv_index = lines( mt_stack ).
  
  