Bug report

Bug summary
Usual behaviour for supressing plots (by enabling plt.ioff()) no longer working since update to latest version of conda.

Code for reproduction

import numpy as np
import matplotlib.pyplot as plt

x = np.random.rand(10)
y = np.random.rand(10)

plt.ioff()
plt.plot(x, y)

Actual outcome
In Spyder IDE, still generates figure window.

Expected outcome
Figure window should not appear. plt.ioff() should disable interactive mode, and require a plt.show() call to generate figure window.

Matplotlib version

• Operating system: Windows 10
• Matplotlib version: 3.1.0
• Matplotlib backend (print(matplotlib.get_backend())): Qt5Agg
• Python version: 3.7.3
• Jupyter version (if applicable):
• Other libraries: numpy 1.16.4

conda

Default channel (via https://www.anaconda.com/distribution/ )