diff --git a/libs/ardour/ardour/session.h b/libs/ardour/ardour/session.h
index bca3970f08..0fb75a52ed 100644
--- a/libs/ardour/ardour/session.h
+++ b/libs/ardour/ardour/session.h
@@ -1218,6 +1218,7 @@ public:
 	bool apply_nth_mixer_scene (size_t, RouteList const&);
 	void store_nth_mixer_scene (size_t);
 	bool nth_mixer_scene_valid (size_t) const;
+	size_t last_touched_mixer_scene_idx () {return _last_touched_mixer_scene_idx;}
 
 	boost::shared_ptr<MixerScene>              nth_mixer_scene (size_t, bool create_if_missing = false);
 	std::vector<boost::shared_ptr<MixerScene>> mixer_scenes () const;
@@ -1437,6 +1438,7 @@ private:
 	bool                    _session_range_is_free;
 	bool                    _silent;
 	samplecnt_t             _remaining_latency_preroll;
+	size_t                  _last_touched_mixer_scene_idx;
 
 	// varispeed playback -- TODO: move out of session to backend.
 	double                  _engine_speed;
diff --git a/libs/ardour/session.cc b/libs/ardour/session.cc
index f8de974212..b18e1f41f3 100644
--- a/libs/ardour/session.cc
+++ b/libs/ardour/session.cc
@@ -198,6 +198,7 @@ Session::Session (AudioEngine &eng,
 	, _session_range_is_free (true)
 	, _silent (false)
 	, _remaining_latency_preroll (0)
+	, _last_touched_mixer_scene_idx (999)
 	, _engine_speed (1.0)
 	, _signalled_varispeed (0)
 	, auto_play_legal (false)
@@ -7537,6 +7538,8 @@ Session::apply_nth_mixer_scene (size_t nth)
 		scene = _mixer_scenes[nth];
 	}
 	assert (scene);
+
+	_last_touched_mixer_scene_idx = nth;
 	return scene->apply ();
 }
 
@@ -7561,6 +7564,7 @@ Session::apply_nth_mixer_scene (size_t nth, RouteList const& rl)
 		r->automatables (acs);
 	}
 
+	_last_touched_mixer_scene_idx = nth;
 	return scene->apply (acs);
 }
 
@@ -7568,6 +7572,8 @@ void
 Session::store_nth_mixer_scene (size_t nth)
 {
 	boost::shared_ptr<MixerScene> scn = nth_mixer_scene (nth, true);
+
+	_last_touched_mixer_scene_idx = nth;
 	scn->snapshot ();
 
 	//calling code is expected to set a name, but we need to initalize with 'something'