diff --git a/libs/ardour/ardour/region.h b/libs/ardour/ardour/region.h
index b0d463c1b6..214e63e991 100644
--- a/libs/ardour/ardour/region.h
+++ b/libs/ardour/ardour/region.h
@@ -111,6 +111,7 @@ public:
 
 	const DataType& data_type () const { return _type; }
 	Temporal::TimeDomain time_domain() const;
+	void globally_change_time_domain (Temporal::TimeDomain from, Temporal::TimeDomain to);
 
 	/** How the region parameters play together:
 	 *
diff --git a/libs/ardour/location.cc b/libs/ardour/location.cc
index 8732d7d58e..7195fcba71 100644
--- a/libs/ardour/location.cc
+++ b/libs/ardour/location.cc
@@ -775,6 +775,8 @@ Location::globally_change_time_domain (Temporal::TimeDomain from, Temporal::Time
 
 		domain_swap->add (_start);
 		domain_swap->add (_end);
+	} else {
+		std::cerr << name() << " wrong domain: " << _start << " .. " << _end << std::endl;
 	}
 }
 
@@ -1735,6 +1737,7 @@ Locations::clear_cue_markers (samplepos_t start, samplepos_t end)
 void
 Locations::globally_change_time_domain (Temporal::TimeDomain from, Temporal::TimeDomain to)
 {
+	std::cerr << "L-gctd on " << locations.size() << std::endl;
 	Glib::Threads::RWLock::WriterLock lm (_lock);
 	for (auto & l : locations) {
 		l->globally_change_time_domain (from, to);
diff --git a/libs/ardour/playlist.cc b/libs/ardour/playlist.cc
index f7c3606e32..445caedbbe 100644
--- a/libs/ardour/playlist.cc
+++ b/libs/ardour/playlist.cc
@@ -3510,4 +3510,8 @@ Playlist::time_domain() const
 void
 Playlist::globally_change_time_domain (Temporal::TimeDomain from, Temporal::TimeDomain to)
 {
+	RegionReadLock rlock (this);
+	for (auto & region  : regions) {
+		region->globally_change_time_domain (from, to);
+	}
 }
diff --git a/libs/ardour/region.cc b/libs/ardour/region.cc
index 241ca249b1..325dadf242 100644
--- a/libs/ardour/region.cc
+++ b/libs/ardour/region.cc
@@ -2171,3 +2171,15 @@ Region::time_domain() const
 
 	return Temporal::BeatTime;
 }
+
+void
+Region::globally_change_time_domain (Temporal::TimeDomain from, Temporal::TimeDomain to)
+{
+	assert (Temporal::domain_swap);
+
+	if (_length.val().time_domain() == from) {
+		timecnt_t& l (_length.non_const_val());
+		l.set_time_domain (to);
+		Temporal::domain_swap->add (l);
+	}
+}
diff --git a/libs/pbd/pbd/properties.h b/libs/pbd/pbd/properties.h
index f4db3b0eb8..8ee2ab0c3b 100644
--- a/libs/pbd/pbd/properties.h
+++ b/libs/pbd/pbd/properties.h
@@ -111,6 +111,10 @@ public:
 		return _current;
 	}
 
+	T& non_const_val () {
+		return _current;
+	}
+
 	/* MANAGEMENT OF Stateful State */
 
 	bool set_value (XMLNode const & node) {
diff --git a/libs/temporal/tempo.cc b/libs/temporal/tempo.cc
index 6dd8ec03c8..618a09d465 100644
--- a/libs/temporal/tempo.cc
+++ b/libs/temporal/tempo.cc
@@ -843,7 +843,6 @@ TempoMap::add_meter (MeterPoint* mp)
 void
 TempoMap::change_tempo (TempoPoint & p, Tempo const & t)
 {
-	std::cerr << "overwrite " << ((Tempo*)&p)->note_types_per_minute() << " with " << t.note_types_per_minute() << std::endl;
 	*((Tempo*)&p) = t;
 	reset_starting_at (p.sclock());
 }
@@ -4156,6 +4155,7 @@ DomainSwapInformation::clear ()
 void
 DomainSwapInformation::undo ()
 {
+	std::cerr << "DSI::undo on " << counts.size() << " lengths and " << positions.size() << " positions\n";
 	for (auto & c : counts) {
 		c->set_time_domain (previous);
 	}