title: How can I deactivate 'Warning: Source ID 510 was not found when attempting to remove it - GLib.source_remove(self._idle_event_id)'?
body: <p>When I execute</p>
  
  <pre><code>#!/usr/bin/env python
  
  import matplotlib.pyplot as plt
  
  plt.plot([1, 2, 3, 4])
  plt.show()
  </code></pre>
  
  <p>(and more complex examples) I get</p>
  
  <pre><code>/usr/local/lib/python3.4/dist-packages/
  matplotlib/backends/backend_gtk3.py:215: Warning: 
  Source ID 7 was not found when attempting to remove it
      GLib.source_remove(self._idle_event_id)
  </code></pre>
  
  <p>What causes this and how can I get rid of these warnings?</p>
  
  <p>I know that I can use</p>
  
  <pre><code>import warnings
  warnings.simplefilter("ignore")
  </code></pre>
  
  <p>to get rid of all warnings, but that is not what I am asking for. I want to have warnings, but none from matplotlib (especially the one from above).</p>