title: How to remove the window title of a matplotlib figure when using the widget backend
body: <p>I use the widget backend to embed an interactive matplotlib figure in an <code>ipywidgets.GridBox</code>.
  The window title takes up too much space and I want to remove it.
  With <code>plt.figure(' ')</code> it becomes invisible but even with <code>fig.tight_layout()</code> the space is still reserved and takes up useless space in my layout.
  Below is a minimal example.</p>
  
  <pre><code>import matplotlib.pyplot as plt
  %matplotlib widget
  plt.ioff()
  fig = plt.figure('remove the title')
  plt.plot([0,1],[0,1])
  fig.tight_layout()
  display(fig.canvas)
  </code></pre>
  
  <p>I found a few examples <a href="https://github.com/matplotlib/jupyter-matplotlib" rel="nofollow noreferrer">here</a> but no complete list of backend specific options. 
  In this related post a solution for the notebook backend is given. <a href="https://stackoverflow.com/questions/52620922/what-is-the-official-name-of-this-title-bar-from-matplotlib-how-to-hide-it?noredirect=1&amp;lq=1">what is the official name of this title bar from matplotlib, how to hide it</a></p>