Notebook Outputs flicker and slow scrolling

[DonJayamanne]

Does this issue occur when all extensions are disabled?: Yes/No

• VS Code Version: Latest
• OS Version: OSX

Steps to Reproduce:

1. Open attached notebook
2. Scroll down with keyboard (at least 10-20 cells)
3. Next Scroll 1/2 way down by dragging scroll bar
4. Wait a few seconds, and outputs will appear and will start flashing
5. Repeat step 3
6. Now there are plenty of outputs without anything displayed and scrolling using keyboard or mouse is very slow

I dont recall seeing this in the past
Not sure when this flickering appeared.

reallylargenotebook copy.ipynb.zip