title: matplotlib close does not close the window
body: <p>I have noticed that when I run:</p>
  
  <pre><code>import pylab as pl
  pl.ion()
  # Plot something
  pl.show()
  pl.close()
  </code></pre>
  
  <p>The last statement does not fully close the Figure. The figure goes dark, and the contents go away, but the Figure stays on the screen until I exit IPython as shown below </p>
  
  <p>&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; <img src="https://i.stack.imgur.com/dfQfH.png" alt="enter image description here"></p>
  
  <p>I am using the latest stable version of matplotlib (<strong>1.3.1</strong>) using an Anaconda distribution, on Linux 64 bit, and I connect remotely using <code>ssh -X</code>.</p>
  
  <p>The backend I am using is below:</p>
  
  <pre><code>backend : QT4Agg
  backend.qt4 : PySide
  </code></pre>