diff --git a/gtk2_ardour/port_matrix.cc b/gtk2_ardour/port_matrix.cc
index f26a78a722..88987f03ef 100644
--- a/gtk2_ardour/port_matrix.cc
+++ b/gtk2_ardour/port_matrix.cc
@@ -121,7 +121,7 @@ PortMatrix::init ()
 {
 	select_arrangement ();
 
-	/* Signal handling is kind of split into two parts:
+	/* Signal handling is kind of split into three parts:
 	 *
 	 * 1.  When _ports[] changes, we call setup().  This essentially sorts out our visual
 	 *     representation of the information in _ports[].
@@ -129,6 +129,8 @@ PortMatrix::init ()
 	 * 2.  When certain other things change, we need to get our subclass to clear and
 	 *     re-fill _ports[], which in turn causes appropriate signals to be raised to
 	 *     hook into part (1).
+	 *
+	 * 3.  Assorted other signals.
 	 */
 
 
@@ -142,11 +144,6 @@ PortMatrix::init ()
 		_ports[i].BundleChanged.connect (_bundle_changed_connections, invalidator (*this), boost::bind (&PortMatrix::setup, this), gui_context());
 	}
 
-	/* scrolling stuff */
-	_hscroll.signal_value_changed().connect (sigc::mem_fun (*this, &PortMatrix::hscroll_changed));
-	_vscroll.signal_value_changed().connect (sigc::mem_fun (*this, &PortMatrix::vscroll_changed));
-
-
 	/* Part 2: notice when things have changed that require our subclass to clear and refill _ports[] */
 	
 	/* watch for routes being added or removed */
@@ -158,6 +155,14 @@ PortMatrix::init ()
 	/* and also ports */
 	_session->engine().PortRegisteredOrUnregistered.connect (_session_connections, invalidator (*this), boost::bind (&PortMatrix::setup_global_ports, this), gui_context());
 
+
+	/* Part 3: other stuff */
+	
+	_session->engine().PortConnectedOrDisconnected.connect (_session_connections, invalidator (*this), boost::bind (&PortMatrix::port_connected_or_disconnected, this), gui_context ());
+
+	_hscroll.signal_value_changed().connect (sigc::mem_fun (*this, &PortMatrix::hscroll_changed));
+	_vscroll.signal_value_changed().connect (sigc::mem_fun (*this, &PortMatrix::vscroll_changed));
+
 	reconnect_to_routes ();
 	
 	setup ();
@@ -829,3 +834,9 @@ PortMatrix::add_disassociate_option (Menu_Helpers::MenuList& m, boost::weak_ptr<
 	snprintf (buf, sizeof (buf), _("%s all from '%s'"), disassociation_verb().c_str(), escape_underscores (b->channel_name (c)).c_str());
 	m.push_back (MenuElem (buf, sigc::bind (sigc::mem_fun (*this, &PortMatrix::disassociate_all_on_channel), w, c, d)));
 }
+
+void
+PortMatrix::port_connected_or_disconnected ()
+{
+	_body->rebuild_and_draw_grid ();
+}
diff --git a/gtk2_ardour/port_matrix.h b/gtk2_ardour/port_matrix.h
index a33d8c2910..0c0a52a1a1 100644
--- a/gtk2_ardour/port_matrix.h
+++ b/gtk2_ardour/port_matrix.h
@@ -189,6 +189,7 @@ private:
 	void session_going_away ();
 	void add_remove_option (Gtk::Menu_Helpers::MenuList &, boost::weak_ptr<ARDOUR::Bundle>, int);
 	void add_disassociate_option (Gtk::Menu_Helpers::MenuList &, boost::weak_ptr<ARDOUR::Bundle>, int, int);
+	void port_connected_or_disconnected ();
 
 	Gtk::Window* _parent;
 
diff --git a/libs/ardour/ardour/audioengine.h b/libs/ardour/ardour/audioengine.h
index ac521fbd4c..e630e1a95e 100644
--- a/libs/ardour/ardour/audioengine.h
+++ b/libs/ardour/ardour/audioengine.h
@@ -230,10 +230,12 @@ _	   the regular process() call to session->process() is not made.
 	PBD::Signal0<void> Running;
 	PBD::Signal0<void> Stopped;
 
-	/* this signal is emitted if a JACK port is registered or unregistered */
-
+	/** Emitted if a JACK port is registered or unregistered */
 	PBD::Signal0<void> PortRegisteredOrUnregistered;
 
+	/** Emitted if a JACK port is connected or disconnected */
+	PBD::Signal0<void> PortConnectedOrDisconnected;
+
 	std::string make_port_name_relative (std::string);
 	std::string make_port_name_non_relative (std::string);
 
@@ -288,6 +290,7 @@ _	   the regular process() call to session->process() is not made.
 	static int  _jack_sync_callback (jack_transport_state_t, jack_position_t*, void *arg);
 	static void _freewheel_callback (int , void *arg);
 	static void _registration_callback (jack_port_id_t, int, void *);
+	static void _connect_callback (jack_port_id_t, jack_port_id_t, int, void *);
 
 	void jack_timebase_callback (jack_transport_state_t, nframes_t, jack_position_t*, int);
 	int  jack_sync_callback (jack_transport_state_t, jack_position_t*);
diff --git a/libs/ardour/audioengine.cc b/libs/ardour/audioengine.cc
index 6ffe0f6048..db1c4f2ef5 100644
--- a/libs/ardour/audioengine.cc
+++ b/libs/ardour/audioengine.cc
@@ -195,6 +195,7 @@ AudioEngine::start ()
 		jack_set_sync_callback (_priv_jack, _jack_sync_callback, this);
 		jack_set_freewheel_callback (_priv_jack, _freewheel_callback, this);
 		jack_set_port_registration_callback (_priv_jack, _registration_callback, this);
+		jack_set_port_connect_callback (_priv_jack, _connect_callback, this);
 
 		if (_session && _session->config.get_jack_time_master()) {
 			jack_set_timebase_callback (_priv_jack, 0, _jack_timebase_callback, this);
@@ -348,6 +349,13 @@ AudioEngine::_registration_callback (jack_port_id_t /*id*/, int /*reg*/, void* a
 	ae->PortRegisteredOrUnregistered (); /* EMIT SIGNAL */
 }
 
+void
+AudioEngine::_connect_callback (jack_port_id_t /*id_a*/, jack_port_id_t /*id_b*/, int /*conn*/, void* arg)
+{
+	AudioEngine* ae = static_cast<AudioEngine*> (arg);
+	ae->PortConnectedOrDisconnected (); /* EMIT SIGNAL */
+}
+
 void
 AudioEngine::split_cycle (nframes_t offset)
 {