Bug report

The following code example uses the RectangleSelector widget, so that we should see a continuously updated rectangular patch over the plot. However, nothing can be seen, unless we setuseblit=False.

Code for reproduction

#!/usr/bin/env python3importmatplotlibfrommatplotlib.widgetsimportRectangleSelectorif__name__=='__main__':matplotlib.use('wxagg')importmatplotlib.pyplotaspltfigure=plt.figure()rect=RectangleSelector(figure.gca(), (lambdae1,e2:print(e1,e2)),useblit=True)plt.show()

Matplotlib version

• Operating system: ubuntu 17.10
• Matplotlib version: 2.2.2
• Matplotlib backend: wxagg
• Python version: 3.6.3
• Other libraries: wxpython 4.0.1

Everything was installed from virtualenv + pip.