anchor.diff:  
   %% @doc release the bp_step function when we executed a bp_step
   -spec bp_step_done(comm:message(), gc_state()) -> gc_state().
  +bp_step_done(_, State)
  +  when not element(?BP_ACTIVE, State)
  +       orelse not element(?BP_STEPPED, State) ->
  +    State;
   bp_step_done(Msg, State) ->
  -    case gc_bpactive(State) andalso gc_bpstepped(State) of
  -        true ->
  -            ?TRACE_BP_STEPS("step done ~.0p~n", [Msg]),
  -            comm:send_local(gc_bpstepper(State),
  -                            {'$gen_component', bp, breakpoint, step_done,
  -                             self(), gc_mod(State), gc_hand(State), Msg}),
  -            T1State = gc_set_bpstepper(State, unknown),
  -            gc_set_bpstepped(T1State, false);
  -        _ -> State
  -    end.
  -
  --spec gc_new(module(), handler(), list()) -> gc_state().
  -gc_new(Module, Handler, Options) ->
  +    ?TRACE_BP_STEPS("step done ~.0p~n", [Msg]),
  +    comm:send_local(gc_bpstepper(State),
  +                    {'$gen_component', bp, breakpoint, step_done,
  +                     self(), gc_mod(State), gc_hand(State), Msg}),
  +    T1State = gc_set_bpstepper(State, unknown),
  +    gc_set_bpstepped(T1State, false).
  +
  +
  +-spec gc_new(module(), handler()) -> gc_state().
  +gc_new(Module, Handler) ->
       {Module, Handler,
  -     no_user_state_yet,
  -     Options, _Slowest = 0.0,
  +%     Options, _Slowest = 0.0,
        _BPs = [], _BPActive = false,
        _BPHoldbackQueue = [], _BPStepped = false,
        _BPStepperPid = unknown
  
positive.code: %%   not in a breakpoint. A selective receive of breakpoint messages,
  %%   provides further bp instructions when needed inside a bp.
  %%%%%%%%%%%%%%%%%%%%
  -spec on(comm:message(), gc_state()) -> gc_state() | ok.
  on(GCMsg, State) when is_tuple(GCMsg)
                        andalso '$gen_component' =:= element(1, GCMsg) ->
      on_gc_msg(GCMsg, State);
  on({ping, Pid}, State) ->
      %% handle failure detector messages
      comm:send(Pid, {pong}, [{channel, prio}]),
      State;
  on({send_to_group_member, Processname, Msg}, State) ->
      %% forward a message to group member by its process name
      %% initiated via comm:send/3 with group_member
      Pid = pid_groups:get_my(Processname),
  
negative.code: -type gc_state() ::
          { module(),
            handler(),
            [bp()],             %% registered breakpoints
            boolean(),          %% bp active?
            [bp_msg()],         %% queued bp messages
  