title: can't show the custom menu on window
body: <p>I have a custom menu class inherit from <code>Tkinter.Menu</code>. I use it in the root window like<br>
  this:</p>
  
  <pre><code>root = Tk()
  menu = customMenu(root)
  root.config(menu = menu)
  mainloop()
  </code></pre>
  
  <p>Can anyone tells me what's wrong, please.</p>