Notebook editor : "Insert cell below" is bugged

[ErwanDL]

Bug: Notebook Editor, Interactive Window, Python Editor cells

When clicking on the "Insert cell below" on the left-hand side of a cell (let's name it current-cell), the new cell is inserted below current-cell but all content in the cells that were below current-cell is also shifted upwards by one cell.

As a result, it is as if the new cell had been inserted at the very bottom of the notebook (pay attention to the cell numbers).

Steps to cause the bug to occur

1. Open a Jupyter notebook in VSCode.
2. Type some content in the first cell, for example :

a = 3
print(a)

3. Add a new cell below it and type some more content in it, for example :

b = 3
print(b)

4. Execute the cells with Shift + Enter : the values of a and b should be printed.
5. Click on the "Insert cell below" button of the first cell.

Actual & Expected behavior

• Actual behavior : the new cell is inserted below the first cell, but the content of the second cell (b = 4) has been shifted upwards into this new cell. Therefore, what previously was the second cell is now empty, and at the bottom of the notebook.

• Expected behavior : the new cell is inserted below the first cell and remains empty. What previously was the second cell should keep its content and now be in third position.

Your Jupyter and/or Python environment

Please provide as much info as you readily know

• Jupyter server running: Local
• Extension version: 2019.10.44104
• VS Code version: 1.39.2
• Setting python.jediEnabled: false
• Python and/or Anaconda version: 3.7.4 (no Anaconda)
• OS: macOS Mojave v10.14.5
• Virtual environment: none

Developer Tools Console Output

No output in the console when executing the aforementioned steps.

[DonJayamanne]

Thanks for reporting this issue, I believe this is a regression and we'll look into this asap.

[ErwanDL]

@DonJayamanne I am actually looking to make my first open source contributions to VSCode, but I am a newcomer in the open source world.

Is this an issue that you think I could try to address myself ? Or do you have any advice on some issues that I should try to fix as a beginner in order to get started ? Thanks

[rchiodo]

This seems to only happen after moving cells.

[rchiodo]

I would hazard a guess it has to do with monaco editor ids not being in sync. It looks like the new cell is picking up the old monaco editor.

[IanMatthewHuff]

Validated.