protected void OnAddAssembly()
        {
            NUnitAssemblyGroupProjectConfiguration config = (NUnitAssemblyGroupProjectConfiguration) CurrentNode.DataItem;

            FileSelector fdiag  = new FileSelector (GettextCatalog.GetString ("Add files"));
            try
            {
                fdiag.SelectMultiple = true;

                int result = fdiag.Run ();
                if (result != (int) Gtk.ResponseType.Ok)
                    return;

                foreach (string file in fdiag.Filenames)
                    config.Assemblies.Add (new TestAssembly (file));

                Runtime.ProjectService.SaveCombine();
            }
            finally {
                fdiag.Destroy ();
            }
        }