title: tkinter protocol WM_DELETE_WINDOW not working on extra windows
body: <p>I want to run some extra windows in my tkinter app (tkinter 8.6, python 3.5, ubuntu xenial). while I can pick up the delete window protocol OK from the main app, it never gets called on additional windows.I want to let the user close the window with the 'X', but I do need to know when they do this.</p>
  
  <p>I expect the answer will be depressingly obvious once I see it!</p>
  
  <p>This simple test app demonstrates.....</p>
  
  <pre><code>#!/usr/bin/python3
  
  import tkinter
  
  class app(tkinter.Tk):
      def __init__(self):
          super().__init__()
          self.child1 = None
          self.geometry('600x400')
          w = tkinter.Button(self, command=self.bclick, text='button1')
          w.pack()
          self.protocol("WM_DELETE_WINDOW", self.appClose)
  
      def bclick(self):
          if self.child1 == None:
              self.child1 = tkinter.Toplevel()
          else:
              self.child1.destroy()
              self.child1 = None
  
      def appClose(self):
          print('main app close')
          self.destroy()
  
  class wind1(tkinter.Toplevel):
      def __init__(self):
          super().__init__()
          self.title('window 1')
          self.protocol("WM_DELETE_WINDOW", self.window1Close)
          self.geometry('600x400')
  
      def window1Close(self):
          print("window1Close")
          self.destroy()
  
  if __name__=="__main__":
      print(tkinter.TkVersion)
      app().mainloop()
  </code></pre>