Bug report

Bug summary

plt.subplot eats my subplots. But it doesn't completely digest them, since they are still there, just not shown.

Creating a subplot grid with plt.subplots and in addition adding a plt.subplot removes those subplots from the grid, which are under the newly created subplot.
Creating the additional subplot via fig.add_subplot does not remove them.

Code for reproduction

import matplotlib.pyplot as plt
fig, ax = plt.subplots(2,3,
                       subplot_kw={"label" : "A"}, 
                       gridspec_kw={'width_ratios':[1,1,3]})
ax[0,2].plot([1,2,3])

axi = plt.subplot(133, label="B")
axi.plot([7,6,5], color="red")
axi.axis("off")

plt.show()

Actual outcome

Expected outcome

The expected outcome would be the same as with fig.add_subplot:

axi = fig.add_subplot(133, label="B")
axi.plot([7,6,5], color="red")
axi.axis("off")

Matplotlib version

• Operating system: Win 8.1
• Matplotlib version: master
• Matplotlib backend: Qt5Agg
• Python version: 3.6