anchor.diff:                              [H|T] -> {H, T}
                           end,
   		    %% Remove process Next from the `active` set and run it.
  -		    NewActive = set_remove(Active, Next),
  +		    NewActive = sets:del_element(Next, Active),
   		    ?debug_2("Running process ~s.~n", [Next]),
   		    run(Next),
   		    %% Create new state.
  
positive.code: 	    %% If the `active` set is empty and the `blocked` set is non-empty,
  	    %% report a deadlock, else if both sets are empty, report normal
              %% program termination.
  	    case set_is_empty(Active) of
  		true ->
  		    ?debug_1("-----------------------~n"),
  		    ?debug_1("Run terminated.~n~n"),
  		    case set_is_empty(Blocked) of
  			true -> ok;
  			false -> {error, deadlock, State}
  		    end;
  		false ->
                      {Next, Rest} =
                          case StateList of
                              [] ->
  
negative.code: %% next and must be moved to the blocked set.
  handler(block, Pid, #info{blocked = Blocked} = Info, _Misc, DetailsFlag) ->
      Lid = lid:from_pid(Pid),
      NewBlocked = sets:add_element(Lid, Blocked),
      ?debug_1("Process ~s blocks.~n", [Lid]),
      case DetailsFlag of
  	true -> replay_logger:log({block, Lid});
  