Weird editing/focus issues when opening two Jupyter notebooks

[mswiatlo]

• VSCode Version: 1.46.1
• OS Version: OSX 10.15.5

Thanks for a great editor! I'm really enjoying using VSCode for editing python and jupyter notebooks in particular.

Sometimes I would like to have two Juptyer notebooks open simultaneously, either to be executing code in both or to use one as a reference for the other. So, I would like to view them in two columns. I will right-click on the notebook tab, hit 'split right' to open a new column, drag the notebook there, and then open a second notebook in the original column (or any other permutation of these steps).

Then, for a minute or two, things may work fine, but (sometimes) I eventually start losing control in both notebooks. For example, when I am editing inside a cell, the cell will cancel out of edit mode on its own, leaving my typing going nowhere until I notice and re-enter edit mode. How often it takes to do this seems to vary, but it's often just a few seconds, making progress impossible.

Sometimes the tab itself will seem to lose focus-- it's hard to describe, but it's like the 'selected tab' focus (the darkened tab in my theme) will flip back and forward between the notebook and any other tabs in that column.

The maddening thing is that it's somewhat difficult to consistently replicate this. It seems to be particularly sensitive to having both notebooks displayed. Sometimes them being open, but not simultaneously displayed, seems fine. Other times, I can have them both open side by side without issues. Sometimes the problem is immediate in a brand new VSCode window; sometimes even somewhat old windows I've been using for a while are able to handle two notebooks just fine.

The problem seems to occur both when I use the notebooks remotely (via remote-ssh on an Ubuntu 18.04.4 machine) and locally (OSX 10.15.5).

Thanks for your help!

Steps to reproduce:

1. Open two Jupyter notebooks side-by-side in columns
2. Edit in one, go back and forth to the other, etc.
3. Observe sporadic loss of editing/focus control in the notebook

Does this issue occur when all extensions are disabled?: No (since this is a python extension related issue)

[rebornix]

/extPython

[vscode-triage-bot]

It looks like this is caused by the Python extension. Please file it with the repository here. Make sure to check their issue reporting template and provide them relevant information such as the extension version you're using. See also our issue reporting guidelines for more information.

Happy Coding!