diff --git a/Demo/tkinter/guido/switch.py b/Demo/tkinter/guido/switch.py
index 7944039..3b58f7c 100644
--- a/Demo/tkinter/guido/switch.py
+++ b/Demo/tkinter/guido/switch.py
@@ -49,6 +49,7 @@
     app = App()
     app.addpanel("label", LabelPanel)
     app.addpanel("button", ButtonPanel)
+    app.top.mainloop()
 
 if __name__ == '__main__':
     main()