Bug report

Bug summary

With temporary styling, using colors with respect to the color cycle, like 'C0', is ignored if plt.show() is called outside of the with block. It only works properly if plt.show() is called inside the block.

Code for reproduction

This reproduces the bug:

import matplotlib.pyplot as plt

with plt.style.context('seaborn'):
    plt.axhline(0, color='C0')
    plt.axhline(1, color='C1')
    plt.axhline(2, color='C2')
plt.show()

This works fine and is the expected behavior:

import matplotlib.pyplot as plt

with plt.style.context('seaborn'):
    plt.axhline(0, color='C0')
    plt.axhline(1, color='C1')
    plt.axhline(2, color='C2')
    plt.show()

Actual outcome

Please note that other elements of the style are working fine, such as the grid.

Expected outcome

Matplotlib version

• Operating system: Solus Linux
• Matplotlib version: 2.2.2
• Matplotlib backend (print(matplotlib.get_backend())): TkAgg
• Python version: 3.6.5

Using matplotlib packaged by the linux distribution.