title: Tkinter issue with multiple callback functions and use of after()
body: <p>I am working on a very long piece of code and one which I would like to take GUI input more than once in multiple windows. </p>
  
  <p>The code is too long and wouldn't make much sense if I put it in here, but here's the layout of my code: </p>
  
  <p><pre><code>
  callback1():
      do something</p>
  
  <pre><code>tkinter stuff, using callback1()    
  ...
  lots of other code (none to do with tkinter)
  ...
  
  callback2():    
      do something else
  
  tkinter stuff using callback2()
  
  some more code (none to do with tkinter)
  
  mainloop()
  </code></pre>
  
  <p></pre></code></p>
  
  <p>Sorry for the vague structure, but this is more or less the layout of my code. The problem is though, that mainloop() never seems to be reached, and my other code in between the callbacks relies on the input from the GUI and so it crashes. </p>
  
  <p>I've tried:</p>
  
  <p><pre><code>
  callback1():
      do something
      after(500, callback1)</p>
  
  <pre><code>tkinter stuff, using callback1()    
  ...
  lots of other code (none to do with tkinter)
  ...
  
  callback2():    
      do something else
      after(500, callback1)
  
  tkinter stuff using callback2()
  
  some more code (none to do with tkinter)
  
  after(0, callback1)
  after(0, callback2)
  mainloop()
  </code></pre>
  
  <p></pre></code></p>
  
  <p>But had no luck. Can anyone help me with the correct usage of after() (or any other function) so that I can just get the GUI to display? </p>