having the same problems here, and no kidding, it was killing me.
I spent hours and hours to figure the solution and even pycharm can't help. ( Don't know why )
I tried subclass the "backtrader.plot.Plot" but still not working.
If you really want to use spyder, here is the trick :
import backtrader.plot import matplotlib matplotlib.use('QT5Agg') # Your running code cerebro.plot(iplot= False)
Remember to select your Graphic backend to "Qt5" in spyder.
You should see the windows pop out (It can even be maximizing ! how great...)
I am using win10 , Anaconda , Spyder 3.3.2 , Py 3.7.1, Ipyhon 7.2.0
(User from Hong Kong. Thanks for the platform, it's really great.)