diff --git a/gtk2_ardour/video_timeline.cc b/gtk2_ardour/video_timeline.cc
index 9460632e6c..24d8f8ebcc 100644
--- a/gtk2_ardour/video_timeline.cc
+++ b/gtk2_ardour/video_timeline.cc
@@ -163,6 +163,10 @@ VideoTimeLine::close_session ()
 	video_filename = "";
 	video_duration = 0;
 	GuiUpdate("set-xjadeo-sensitive-off");
+	if (open_video_monitor_dialog) {
+		delete open_video_monitor_dialog;
+	}
+	open_video_monitor_dialog = 0;
 }
 
 /** load settings from session */
@@ -216,6 +220,11 @@ VideoTimeLine::set_session (ARDOUR::Session *s)
 		video_file_info(propf->value(), local_file);
 	}
 
+	if (open_video_monitor_dialog) {
+		delete open_video_monitor_dialog;
+	}
+	open_video_monitor_dialog = 0;
+
 	node = _session->extra_xml (X_("Videomonitor"));
 	if (node) {
 		const XMLProperty* prop = node->property (X_("active"));