diff --git a/gtk2_ardour/global_port_matrix.cc b/gtk2_ardour/global_port_matrix.cc
index 0c5ae17264..3aa08bb218 100644
--- a/gtk2_ardour/global_port_matrix.cc
+++ b/gtk2_ardour/global_port_matrix.cc
@@ -53,13 +53,11 @@ GlobalPortMatrix::set_state (BundleChannel c[2], bool s)
 	Bundle::PortList const & in_ports = c[IN].bundle->channel_ports (c[IN].channel);
 	Bundle::PortList const & out_ports = c[OUT].bundle->channel_ports (c[OUT].channel);
 
-        Glib::Mutex::Lock lm (AudioEngine::instance()->process_lock());
-
 	for (Bundle::PortList::const_iterator i = in_ports.begin(); i != in_ports.end(); ++i) {
 		for (Bundle::PortList::const_iterator j = out_ports.begin(); j != out_ports.end(); ++j) {
 
-			Port* p = _session->engine().get_port_by_name_locked (*i);
-			Port* q = _session->engine().get_port_by_name_locked (*j);
+			Port* p = _session->engine().get_port_by_name (*i);
+			Port* q = _session->engine().get_port_by_name (*j);
 
 			if (p) {
 				if (s) {
diff --git a/gtk2_ardour/io_selector.cc b/gtk2_ardour/io_selector.cc
index d440e1397b..3217e2e81f 100644
--- a/gtk2_ardour/io_selector.cc
+++ b/gtk2_ardour/io_selector.cc
@@ -136,12 +136,10 @@ IOSelector::set_state (ARDOUR::BundleChannel c[2], bool s)
 	ARDOUR::Bundle::PortList const & our_ports = c[_ours].bundle->channel_ports (c[_ours].channel);
 	ARDOUR::Bundle::PortList const & other_ports = c[_other].bundle->channel_ports (c[_other].channel);
 
-        Glib::Mutex::Lock lm (AudioEngine::instance()->process_lock());
-
 	for (ARDOUR::Bundle::PortList::const_iterator i = our_ports.begin(); i != our_ports.end(); ++i) {
 		for (ARDOUR::Bundle::PortList::const_iterator j = other_ports.begin(); j != other_ports.end(); ++j) {
 
-			Port* f = _session->engine().get_port_by_name_locked (*i);
+			Port* f = _session->engine().get_port_by_name (*i);
 			if (!f) {
 				return;
 			}
diff --git a/gtk2_ardour/processor_box.cc b/gtk2_ardour/processor_box.cc
index 99875a2a47..52c33ef114 100644
--- a/gtk2_ardour/processor_box.cc
+++ b/gtk2_ardour/processor_box.cc
@@ -44,6 +44,7 @@
 #include "ardour/audio_track.h"
 #include "ardour/audioengine.h"
 #include "ardour/internal_send.h"
+#include "ardour/internal_return.h"
 #include "ardour/ladspa_plugin.h"
 #include "ardour/meter.h"
 #include "ardour/plugin_insert.h"
@@ -1588,6 +1589,11 @@ ProcessorBox::toggle_edit_processor (boost::shared_ptr<Processor> processor)
 
 	} else if ((retrn = boost::dynamic_pointer_cast<Return> (processor)) != 0) {
 
+                if (boost::dynamic_pointer_cast<InternalReturn> (retrn)) {
+                        /* no GUI for these */
+                        return;
+                }
+
 		if (!_session->engine().connected()) {
 			return;
 		}