_engine.GraphReordered.connect_same_thread (*this, boost::bind (&Session::graph_reordered, this));
_engine.MidiSelectionPortsChanged.connect_same_thread (*this, boost::bind (&Session::rewire_midi_selection_ports, this));
_engine.GraphReordered.connect_same_thread (*this, boost::bind (&Session::graph_reordered, this));
_engine.MidiSelectionPortsChanged.connect_same_thread (*this, boost::bind (&Session::rewire_midi_selection_ports, this));