diff --git a/gtk2_ardour/region_view.cc b/gtk2_ardour/region_view.cc
index 69c42a04e0..70ef21e995 100644
--- a/gtk2_ardour/region_view.cc
+++ b/gtk2_ardour/region_view.cc
@@ -574,7 +574,7 @@ RegionView::update_cue_markers ()
 	 * timestamps and some of them may be outside the Region.
 	 */
 
-	for (CueMarkers::iterator c = model_markers.begin(); c != model_markers.end(); c++) {
+	for (CueMarkers::const_iterator c = model_markers.begin(); c != model_markers.end(); c++) {
 
 		ViewCueMarkers::iterator existing = _cue_markers.end();