diff --git a/gtk2_ardour/gui_object.cc b/gtk2_ardour/gui_object.cc
index 3f6b79c8c6..e9f93e0ebc 100644
--- a/gtk2_ardour/gui_object.cc
+++ b/gtk2_ardour/gui_object.cc
@@ -46,7 +46,7 @@ GUIObjectState::get_or_add_node (XMLNode* parent, const string& id)
 	XMLNode* child = get_node (parent, id);
 	if (!child) {
 		child = new XMLNode (X_("Object"));
-		child->add_property (X_("id"), id);
+		child->set_property (X_("id"), id);
 		parent->add_child_nocopy (*child);
 	}
 	return child;
@@ -69,7 +69,7 @@ GUIObjectState::get_or_add_node (const string& id)
 	}
 	//assert (get_node (&_state, id) == 0); // XXX performance penalty due to get_node()
 	XMLNode* child = new XMLNode (X_("Object"));
-	child->add_property (X_("id"), id);
+	child->set_property (X_("id"), id);
 	_state.add_child_nocopy (*child);
 	object_map[id] = child;
 	return child;
diff --git a/gtk2_ardour/gui_object.h b/gtk2_ardour/gui_object.h
index 62eeaa9a33..c9082807fb 100644
--- a/gtk2_ardour/gui_object.h
+++ b/gtk2_ardour/gui_object.h
@@ -49,9 +49,7 @@ public:
 
 	template<typename T> void set_property (const std::string& id, const std::string& prop_name, const T& val) {
 		XMLNode* child = get_or_add_node (id);
-		std::stringstream s;
-		s << val;
-		child->add_property (prop_name.c_str(), s.str());
+		child->set_property (prop_name.c_str(), val);
 	}
 
 	/** Remove node with provided id.