Index: gtk2_ardour/route_ui.cc
===================================================================
--- gtk2_ardour/route_ui.cc	(revision 13195)
+++ gtk2_ardour/route_ui.cc	(working copy)
@@ -1346,6 +1346,7 @@
 	
 	gui_object_state().set_property<string> (route_state_id(), X_("color"), buf);
 	_route->gui_changed ("color", (void *) 0); /* EMIT_SIGNAL */
+	_session->set_dirty ();
 }
 
 /** @return GUI state ID for things that are common to the route in all its representations */