Jupyter notebook cell boundary disappears on active cell

[toiletbowlkuku]

Describe the bug

Here is a picture to illustrate the issue:

Reproduction

Enable the theme and open a jupyter notebook with a cell active

System Info

Windows 11, Visual Studio Code

Used Package Manager

n/a

Validations

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• Read the Contributing Guide.
• Check that there isn't already an issue that reports the same bug to avoid creating a duplicate.
• Check that this is a concrete bug. For Q&A, please open a GitHub Discussion instead.
• The provided reproduction is a minimal reproducible of the bug.

Contributions

• I am willing to submit a PR to fix this issue
• I am willing to submit a PR with failing tests (actually just go ahead and do it, thanks!)