Event registry prevents object recycling

*&---------------------------------------------------------------------*
*& Report ZZ_TEST_OBJ_EVT_LIFESPAN
*&---------------------------------------------------------------------*
*&
*&---------------------------------------------------------------------*
REPORT ZZ_TEST_OBJ_EVT_LIFESPAN.

class a definition.
  public section.
    events: e.
    methods: raise.
endclass.

class b definition.
  public section.
    methods:
      m for event e of a,
      constructor,
      deregister.
endclass.

class a implementation.
  method raise.
    raise event e.
  endmethod.
endclass.

class b implementation.
  method m.
    write: / 'ibims'.
  endmethod.
  method deregister.
    set handler m for all instances activation abap_false.
  endmethod.
  method constructor.
    set handler m for all instances activation abap_true.
  endmethod.
endclass.

start-of-selection.
  data(go_a) = new a( ).
  perform start.

form start.
  write: / 'Erster Aufruf'.
  perform test.

  write: / 'Zweiter Aufruf'.
  perform test.
endform.

form test.
  data(lo_b) = new b( ).
  go_a->raise( ).
*  lo_b->deregister( ). " Ist eben nicht automatisch bei Abbau der Referenzvariable LO_B
endform.