diff --git a/gtk2_ardour/editor.h b/gtk2_ardour/editor.h
index 21c8a3a588..5f27d170b1 100644
--- a/gtk2_ardour/editor.h
+++ b/gtk2_ardour/editor.h
@@ -1758,7 +1758,7 @@ private:
 	void mid_tempo_per_region_update (RegionView*);
 	bool ignore_map_change;
 
-	Temporal::TempoMap::WritableSharedPtr begin_tempo_mapping ();
+	Temporal::TempoMap::WritableSharedPtr begin_tempo_mapping (PBD::Command**);
 	void abort_tempo_mapping ();
 	void commit_tempo_mapping (Temporal::TempoMap::WritableSharedPtr&);
 
diff --git a/gtk2_ardour/editor_mouse.cc b/gtk2_ardour/editor_mouse.cc
index c83f770512..425d2e00bf 100644
--- a/gtk2_ardour/editor_mouse.cc
+++ b/gtk2_ardour/editor_mouse.cc
@@ -3012,7 +3012,8 @@ Editor::choose_mapping_drag (ArdourCanvas::Item* item, GdkEvent* event)
 		return;
 	}
 
-	Temporal::TempoMap::WritableSharedPtr map = begin_tempo_mapping ();
+	PBD::Command* swap_undo_command;
+	Temporal::TempoMap::WritableSharedPtr map = begin_tempo_mapping (&swap_undo_command);
 
 	/* Decide between a mid-twist, which we do if the
 	 * pointer is between two tempo markers, and an end-stretch,
@@ -3103,6 +3104,7 @@ Editor::choose_mapping_drag (ArdourCanvas::Item* item, GdkEvent* event)
 
 	if (at_end) {
 		begin_reversible_command (_("tempo mapping: end-stretch"));
+		_session->add_command (swap_undo_command);
 		std::cerr << "END STRETCH\n";
 		_drags->set (new MappingEndDrag (this, item, map, tempo, *focus, *before_state), event);
 		return;
@@ -3111,11 +3113,13 @@ Editor::choose_mapping_drag (ArdourCanvas::Item* item, GdkEvent* event)
 	if (before && focus && after) {
 		std::cerr << "TWIST\n";
 		begin_reversible_command (_("tempo mapping: mid-twist"));
+		_session->add_command (swap_undo_command);
 		_drags->set (new MappingTwistDrag (this, item, map, *before, *focus, *after, *before_state, ramped), event);
 	} else if (ramped && focus && after) {
 		/* special case 4: user is manipulating a beat line after the INITIAL tempo marker, so there is no prior marker*/
 		std::cerr << "TWIST ON START\n";
 		begin_reversible_command (_("tempo mapping: mid-twist"));
+		_session->add_command (swap_undo_command);
 		before = focus; /* this is unused in MappingTwistDrag, when ramped is true, but let's not pass in garbage */
 		_drags->set (new MappingTwistDrag (this, item, map, *before, *focus, *after, *before_state, ramped), event);
 	} else {
diff --git a/gtk2_ardour/editor_tempodisplay.cc b/gtk2_ardour/editor_tempodisplay.cc
index 1a66417d8e..1a430066ba 100644
--- a/gtk2_ardour/editor_tempodisplay.cc
+++ b/gtk2_ardour/editor_tempodisplay.cc
@@ -813,13 +813,13 @@ Editor::real_remove_meter_marker (Temporal::MeterPoint const * section)
 
 
 Temporal::TempoMap::WritableSharedPtr
-Editor::begin_tempo_mapping ()
+Editor::begin_tempo_mapping (PBD::Command** cmd)
 {
 	TempoMap::WritableSharedPtr wmap = TempoMap::write_copy ();
-	TempoMap::set (wmap);
+	TempoMap::set (wmap); 
 	reassociate_metric_markers (wmap);
 	(void) Temporal::DomainSwapInformation::start (Temporal::BeatTime);
-	_session->globally_change_time_domain (Temporal::BeatTime, Temporal::AudioTime);
+	*cmd = _session->globally_change_time_domain (Temporal::BeatTime, Temporal::AudioTime);
 	return wmap;
 }
 
diff --git a/gtk2_ardour/public_editor.h b/gtk2_ardour/public_editor.h
index 220ea7dfdb..338ddd1e67 100644
--- a/gtk2_ardour/public_editor.h
+++ b/gtk2_ardour/public_editor.h
@@ -528,7 +528,7 @@ public:
 		_commit_tempo_map_edit (map, with_update);
 	}
 
-	virtual Temporal::TempoMap::WritableSharedPtr begin_tempo_mapping () = 0;
+	virtual Temporal::TempoMap::WritableSharedPtr begin_tempo_mapping (PBD::Command**) = 0;
 	virtual void abort_tempo_mapping () = 0;
 	virtual void commit_tempo_mapping (Temporal::TempoMap::WritableSharedPtr& map) = 0;