diff --git a/gtk2_ardour/editor_ops.cc b/gtk2_ardour/editor_ops.cc
index 3a57ae8fd7..b1a06b8c23 100644
--- a/gtk2_ardour/editor_ops.cc
+++ b/gtk2_ardour/editor_ops.cc
@@ -6131,6 +6131,7 @@ Editor::apply_filter (Filter& filter, string command, ProgressReporter* progress
 
 				} else {
 
+					playlist->freeze ();
 					std::vector<boost::shared_ptr<Region> >::iterator res = filter.results.begin ();
 
 					/* first region replaces the old one */
@@ -6142,6 +6143,7 @@ Editor::apply_filter (Filter& filter, string command, ProgressReporter* progress
 						playlist->add_region (*res, (*res)->position());
 						++res;
 					}
+					playlist->thaw ();
 
 				}