diff --git a/libs/evoral/ControlList.cc b/libs/evoral/ControlList.cc
index 6d913c99a7..a6a3395b6f 100644
--- a/libs/evoral/ControlList.cc
+++ b/libs/evoral/ControlList.cc
@@ -732,8 +732,8 @@ ControlList::editor_add_ordered (OrderedPoints const & points, bool with_guard)
 	{
 		Glib::Threads::RWLock::WriterLock lm (_lock);
 
-		Temporal::timepos_t earliest = points.front().when;
-		Temporal::timepos_t latest = points.back().when;
+		Temporal::timepos_t earliest = ensure_time_domain (points.front().when);
+		Temporal::timepos_t latest   = ensure_time_domain (points.back().when);
 
 		assert (earliest <= latest);
 
@@ -742,20 +742,12 @@ ControlList::editor_add_ordered (OrderedPoints const & points, bool with_guard)
 		(void) erase_range_internal (earliest, latest, _events);
 
 		if (with_guard) {
-			ControlEvent cp (earliest, 0.0);
-			double v = unlocked_eval (earliest);
-			iterator     s = lower_bound (_events.begin (), _events.end (), &cp, time_comparator);
-			if (s != _events.end ()) {
-				_events.insert (s, new ControlEvent (earliest, v));
-			}
+			unlocked_invalidate_insert_iterator ();
+			add_guard_point (earliest, -GUARD_POINT_DELTA (*this));
 		}
 		if (with_guard && !distance.is_zero()) {
-			ControlEvent cp (latest, 0.0);
-			double v = unlocked_eval (latest);
-			iterator     s = lower_bound (_events.begin (), _events.end (), &cp, time_comparator);
-			if (s != _events.end ()) {
-				_events.insert (s, new ControlEvent (latest, v));
-			}
+			unlocked_invalidate_insert_iterator ();
+			add_guard_point (latest, GUARD_POINT_DELTA (*this));
 		}
 
 		/* Get the iterator where we should start insertion */