diff --git a/IPython/html/tests/widgets/widget.js b/IPython/html/tests/widgets/widget.js
index 06623d8..e0e89cc 100644
--- a/IPython/html/tests/widgets/widget.js
+++ b/IPython/html/tests/widgets/widget.js
@@ -98,7 +98,7 @@ casper.notebook_test(function () {
                     this.touch();
                 },
             });
-            WidgetManager.register_widget_view('MultiSetView', MultiSetView);
+            IPython.WidgetManager.register_widget_view('MultiSetView', MultiSetView);
         }, {});
     });