diff --git a/libs/ardour/midi_region.cc b/libs/ardour/midi_region.cc
index bdf24f5e08..b1c332072e 100644
--- a/libs/ardour/midi_region.cc
+++ b/libs/ardour/midi_region.cc
@@ -192,10 +192,6 @@ void
 MidiRegion::set_length_internal (framecnt_t len)
 {
 	Region::set_length_internal (len);
-	/* XX this seems wrong. we asked to set the length in 
-	   frames without requesting a new beat.
-	   may cause beat drift due to frame rounding.
-	*/
 	update_length_beats ();
 }
 
@@ -229,11 +225,10 @@ MidiRegion::set_position_internal (framepos_t pos, bool allow_bbt_recompute)
 	Region::set_position_internal (pos, allow_bbt_recompute);
 
 	/* leave _length_beats alone, and change _length to reflect the state of things
-	   at the new position (tempo map may dictate a different number of frames
+	   at the new position (tempo map may dictate a different number of frames).
 	*/
 	BeatsFramesConverter converter (_session.tempo_map(), _position);
 	Region::set_length_internal (converter.to (_length_beats));
-	send_change (Properties::length);
 }
 
 framecnt_t
diff --git a/libs/ardour/region.cc b/libs/ardour/region.cc
index 1b9793313d..105aa3af59 100644
--- a/libs/ardour/region.cc
+++ b/libs/ardour/region.cc
@@ -578,7 +578,19 @@ Region::set_position (framepos_t pos)
 	/* do this even if the position is the same. this helps out
 	   a GUI that has moved its representation already.
 	*/
-	send_change (Properties::position);
+	PropertyChange p_and_l;
+
+	p_and_l.add (Properties::position);
+	/* Currently length change due to position change is only implemented
+	   for MidiRegion (Region has no length in beats).
+	   Notify a length change regardless (its more efficient for MidiRegions),
+	   and when Region has a _length_beats we will need it here anyway).
+	*/
+	if (position_lock_style() == MusicTime) {
+		p_and_l.add (Properties::length);
+	}
+
+	send_change (p_and_l);
 
 }