--- a/src/gen/plug/_manager.py
+++ b/src/gen/plug/_manager.py
@@ -549,7 +549,7 @@
         @param option:      the option class
         @type option:       class that inherits from gen.plug.menu.Option
         @param guioption:   the gui-option class
-        @type guioption:    class that inherits from gtk.Widget.
+        @type guioption:    class that inherits from Gtk.Widget.
         """
         self.__external_opt_dict[option] = guioption;