Index: gtkdoc-scangobj.in
===================================================================
RCS file: /cvs/gnome/gtk-doc/gtkdoc-scangobj.in,v
retrieving revision 1.52
diff -u -p -r1.52 gtkdoc-scangobj.in
--- gtkdoc-scangobj.in	9 Sep 2006 04:44:06 -0000	1.52
+++ gtkdoc-scangobj.in	11 Oct 2006 20:06:46 -0000
@@ -144,8 +157,12 @@ print OUTPUT <<EOT;
      * their signals and properties.
      */
     for (i=0; object_types[i]; i++)
-      if (G_TYPE_IS_CLASSED (object_types[i]))
-      g_type_class_ref (object_types[i]);
+      {
+        if (G_TYPE_IS_CLASSED (object_types[i]))
+          g_type_class_ref (object_types[i]);
+        if (G_TYPE_IS_INTERFACE (object_types[i]))
+          g_type_default_interface_ref (object_types[i])
+      }
 
     return object_types;
 }
