title: access properties of widget inside canvas.create_window
body: <p>I am having the following problem. I am making a tkinter GUI, and  I need to access an object that is inside a canvas, inside a Canvas.create_window widget, packed with some other objects. For example:</p>
  
  <pre><code>import Tkinter as tk
  class Demo:
      def __init__(self, master):
          self.canvas = tk.Canvas()
          self.canvas.pack(fill="both", expand=True)
          f = tk.Frame(self.canvas)
          f.pack()
          self.container = self.canvas.create_window(50,50, window = f)
          l = tk.Label(f, text='abc')
          e = tk.Entry(f, width = 5)
          l.pack()
          e.pack()
  if __name__ == '__main__':
      root = tk.Tk()
      app = Demo(root)
      root.mainloop()
  </code></pre>
  
  <p>I am trying to edit the text of the l label (which is currently 'abc'), when some other event is triggered. I suppose I need to use canvas.itemconfig, but I can't find a way to pass to this function the correct reference to the label. Any Ideas?
  Thank you</p>