title: plt.show() making terminal hang
body: <p>At the end of the last function I call in one of my programs, I have the following code to plot a simple color plot.</p>
  
  <pre><code>plt.figure()
  plt.pcolormesh(X,Y,Z)
  plt.colorbar()
  plt.show()
  </code></pre>
  
  <p>Afterwords I return to main and my program is complete.  The plot displays as expected, however when I go to close it using the x button in the corner (on ubuntu), my program doesn't end.  It just hangs there with a process running.  How can I correct this?</p>