[BUG] Conflicts between nbAgg backend and visualpython

Describe the bug Bug report from community : Community Bug Report Thanks to GF LIU :)

To Reproduce Steps to reproduce the behavior:

1. Enable visualpython
2. Run code from jupyter notebook

import numpy as np
import matplotlib.pyplot as plt
%matplotlib notebook

x = np.linspace(0, 10, 100)
y = np.linspace(0, 10, 100)
fig, ax = plt.subplots(dpi=60)
ax.plot(x, y,)
fig.show()

3. Check output area's button image

Expected behavior To show button images correctly

Screenshots (Attached above)

Desktop (please complete the following information):

• OS: Windows 10
• Browser: Chrome

VisualPython Information (please complete the following information):

• Version 2.2.12

Need to fix visualpython not to apply vp's style outside its area. Some styles need more parent selector to restrict its area.