Heatmap coloring disappears when resizing notebook window

[devnoname120]

import numpy as np
import plotly.graph_objs as go
from plotly.offline import init_notebook_mode, iplot

init_notebook_mode(connected=True)

x = np.random.randn(2000)
y = np.random.randn(2000)
iplot([go.Histogram2dContour(x=x, y=y, contours=dict(coloring='heatmap'))], show_link=False)

How to reproduce:

• Open a Jupyter notebook, and paste the code above.
• Run the notebook.
• Resize the browser window.

Information:

• Python 3.6.0.
• Plotly 3.8.1 installed using conda.
• Reproduced on both Firefox 66.0.5 (64-bit) and Chromium 73.0.3683.86.

Extra information:

noname@noname-pc:~$ conda list | grep -iE 'jupy|ipyt'
ipython                   7.4.0                    pypi_0    pypi
ipython-genutils          0.2.0                    pypi_0    pypi
ipython_genutils          0.2.0                    py36_0  
jupyter_client            5.2.4                    py36_0  
jupyter_core              4.4.0                    py36_0  

[jonmmease]

Thanks for taking the time to make this thorough report @devnoname120, I was able to reproduce this directly in plotly.js, so I'm going to move the issue over there at plotly/plotly.js#3894. Thanks!