title: Cannot change to a different GUI toolkit: notebook - Warning in Jupyter
body: <p>I want to use the interactive plots in jupyter, but when switching the backend to notebook, I get the warning:
  Warning: Cannot change to a different GUI toolkit: notebook. Using qt5 instead.</p>
  
  <p>This happens on Windows 10, Anaconda 1.8.7, jupyter 5.5.0, python 3.6.5 and matplotlib 2.2.2.</p>
  
  <p>Minimal working example:</p>
  
  <pre><code>import matplotlib.pyplot as plt
  %matplotlib notebook
  </code></pre>
  
  <p>Output: </p>
  
  <pre><code>Warning: Cannot change to a different GUI toolkit: notebook. Using qt5 instead.
  </code></pre>
  
  <p>I found some question here where the problem is the other way around, but could not find anyone having this problem yet.
  In some cases, importing ipympl is mentioned as a solution, but this does not change anything in my case.</p>
  
  <p>Any hints? </p>