title: Window doesn't appear using Tkinter
body: <p>This is the file I launch with python :</p>
  
  <pre><code>from Tkinter import *
  
  # Esempio di GUI
  
  def main():
      w1 = Tk()
      w1.title("Finestra 1")
      f1 = Frame(w1)
      f1.pack()
      w1.mainloop()
  
  main()
  </code></pre>
  
  <p>The program is in execution, but I don't see any window appearing.
  I have to close the terminal window to stop, I don't get why.</p>