diff --git a/libs/ardour/midi_ui.cc b/libs/ardour/midi_ui.cc
index 770a371..7493ac0 100644
--- a/libs/ardour/midi_ui.cc
+++ b/libs/ardour/midi_ui.cc
@@ -75,6 +75,7 @@ MidiControlUI::do_request (MidiUIRequest* req)
 		}
 #endif
 
+		cout << "do " << req << "\n";
 		req->the_slot ();
 
 	} else if (req->type == Quit) {
diff --git a/libs/pbd/pbd/abstract_ui.cc b/libs/pbd/pbd/abstract_ui.cc
index 4c13ec1..4eb0b7d 100644
--- a/libs/pbd/pbd/abstract_ui.cc
+++ b/libs/pbd/pbd/abstract_ui.cc
@@ -222,6 +222,8 @@ AbstractUI<RequestObject>::call_slot (InvalidationRecord* invalidation, const bo
 	}
 
 	RequestObject *req = get_request (BaseUI::CallSlot);
+	cout << "call_slot req " << req << "\n";
+	PBD::stacktrace (cout, 10);
 	
 	if (req == 0) {
 		return;