title: Python tkinter, canvas don't show
body: <p>The canvas dosen't work for me with tkinter, i got menu working, also toplevel windows but not canvas. Here is my example:</p>
  
  <pre><code>class Interface(Frame):
      def __init__(self, master=None):
          self.__loadSettings()
          Frame.__init__(self,master)
          self.m=Menu(self)
          menu = Menu(self.m, tearoff=0)
          self.m.add_cascade(label="File", menu=menu)
          menu.add_command(label="New", command=self.__newGame)
          menu = Menu(self.m, tearoff=0)
          self.m.add_cascade(label="Edit", menu=menu)
          menu.add_command(label="Settings", command=self.__settings)
          self.master.config(menu=self.m)
          self.canvas= Canvas(self,height=500, width=500)
          self.canvas.create_rectangle(100,100,400,400, fill="blue")
  
  root = Tk()
  ui = Interface(root)
  ui.mainloop()
  </code></pre>
  
  <p>The windows and menu works, but not the canvas.</p>