title: Cannot invoke button command: application has been destroyed
body: <p>Given below is the code for creating independent windows using Tkinter and Python:</p>
  
  <pre><code>import Tkinter
  
  Tkinter.NoDefaultRoot()
  
  win1=Tkinter.Tk()
  win2=Tkinter.Tk()
  
  Tkinter.Button(win1, text='Woho!',command=win1.destroy()).pack()
  Tkinter.Button(win2, text='Woho!',command=win2.destroy()).pack()
  
  win1.mainloop()
  </code></pre>
  
  <p>On execution it displays:</p>
  
  <pre><code>Traceback (most recent call last):
    File "C:\Users\Administrator\Desktop\eclipse\Python Projects\Project 1\Source1\mod.py", line 8, in &lt;module&gt;
      Tkinter.Button(win1, text='Woho!',command=win1.destroy()).pack()
    File "C:\Python27\lib\lib-tk\Tkinter.py", line 2106, in __init__
      Widget.__init__(self, master, 'button', cnf, kw)
    File "C:\Python27\lib\lib-tk\Tkinter.py", line 2036, in __init__
      (widgetName, self._w) + extra + self._options(cnf))
  _tkinter.TclError: can't invoke "button" command:  application has been destroyed
  </code></pre>
  
  <p>I am new to Python and hence so not understand what it means. Where am I going wrong?</p>