anchor.diff:      T1GCState = on_bp(Msg, UState, GCState),
       Module  = gc_mod(T1GCState),
       Handler = gc_hand(T1GCState),
  -    T2State =
  -        try Handler(Msg, UState)
  -        catch Level:Reason ->
  -                Stacktrace = erlang:get_stacktrace(),
  -                case Stacktrace of
  -                    %% erlang < R15 : {Module, Handler, [Msg, State]}
  -                    %% erlang >= R15: {Module, Handler, [Msg, State], _}
  -                    [T | _] when
  -                          erlang:element(1, T) =:= Module andalso
  -                          %% erlang:element(2, T) =:= Handler andalso
  -                          erlang:element(3, T) =:= [Msg, UState] andalso
  -                          Reason =:= function_clause andalso
  -                          Level =:= error ->
  -                        on_unknown_event(Msg, UState, T1GCState),
  -                        {'$gc_unknown_event'};
  -                    _ ->
  -                        on_exception(Msg, Level, Reason, Stacktrace,
  -                                     UState, T1GCState),
  -                        {'$gc_exception'}
  -                end
  -        end,
  -    case T2State of
  +    try Handler(Msg, UState) of
           kill ->
               log:log(info, "[ gen_component ] ~.0p killed (~.0p:~.0p/2):",
                       [self(), Module, Handler]),
  
positive.code:     T1GCState = on_bp(Msg, UState, GCState),
      Module  = gc_mod(T1GCState),
      Handler = gc_hand(T1GCState),
      T2State =
          try Handler(Msg, UState)
          catch Level:Reason ->
                  Stacktrace = erlang:get_stacktrace(),
                  case Stacktrace of
                      %% erlang < R15 : {Module, Handler, [Msg, State]}
                      %% erlang >= R15: {Module, Handler, [Msg, State], _}
                      [T | _] when
                            erlang:element(1, T) =:= Module andalso
                            %% erlang:element(2, T) =:= Handler andalso
                            erlang:element(3, T) =:= [Msg, UState] andalso
                            Reason =:= function_clause andalso
                            Level =:= error ->
                          on_unknown_event(Msg, UState, T1GCState),
                          {'$gc_unknown_event'};
                      _ ->
                          on_exception(Msg, Level, Reason, Stacktrace,
                                       UState, T1GCState),
                          {'$gc_exception'}
                  end
          end,
      case T2State of
          kill ->
              log:log(info, "[ gen_component ] ~.0p killed (~.0p:~.0p/2):",
                      [self(), Module, Handler]),
  
negative.code:                             erlang:throw('unknown gen_component command')
                      end
              end;
          unknown_event ->
              %% drop T2State, as it contains the error message
              on_unknown_event(Msg, UState, T1GCState),
  