diff --git a/python/obitools3/apps/arguments.pyx b/python/obitools3/apps/arguments.pyx
index c521fac..d64ae38 100644
--- a/python/obitools3/apps/arguments.pyx
+++ b/python/obitools3/apps/arguments.pyx
@@ -57,5 +57,6 @@ cpdef buildArgumentParser(str configname,
                 module.addOptions(sub)
             
             sub.set_defaults(**{'%s:module'  % configname : module})
-                        
+            sub.set_defaults(**{'%s:modulename'  % configname : c})
+              
     return parser