anchor.diff:  
     ENDMETHOD.
   
  -ENDCLASS.+ENDCLASS.
  +AT SELECTION-SCREEN ON EXIT-COMMAND.
  +  CASE sy-ucomm.
  +    WHEN 'CBAC'.  "Back
  +      IF lcl_gui=>back( ) IS INITIAL.
  +        LEAVE TO SCREEN 1001.
  +      ENDIF.
  +  ENDCASE.
positive.code:       RAISING lcx_exception.
  
      CLASS-METHODS back
        RAISING lcx_exception.
  
      CLASS-METHODS call_page
  
negative.code:     lv_index = lines( gt_stack ).
  
      IF lv_index = 0.
        r_exit = 'X'.
        RETURN.
      ENDIF.
  
  