# JupyterLab v4.6.3

- Product: JupyterLab (https://whatsnew.fyi/product/jupyterlab)
- Vendor: Project Jupyter
- Date: 2026-08-10
- Version: v4.6.3
- Original notes: https://github.com/jupyterlab/jupyterlab/releases/tag/v4.6.3
- Permalink: https://whatsnew.fyi/product/jupyterlab/releases/v4.6.3

What's New is an index, not a publisher: every entry below links to the vendor's own release notes, which are the authoritative source. Entries are labelled where they are hand-curated sample data, pre-releases, or drawn from a secondary source such as a developer blog.

Reuse: the summaries, labels and curation here are © What's New. Quote freely with attribution and a link back; wholesale republication of the corpus is not permitted — terms: https://whatsnew.fyi/terms. The vendors' own release notes remain their publishers'.

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- **fixed** — Fix Shift-click cell selection after editor text selection
- **fixed** — Fix active cell prompt and source blink in notebook tools and prevent a memory leak
- **fixed** — Update the item positions when an item is removed from reactive toolbar
- **fixed** — Fix variable inspection, document autocomplete and variable inspect/render
- **fixed** — Show starting rather than idle status when changing kernel via SessionContext.changeKernel()

##### 4.6.3

([Full Changelog](https://github.com/jupyterlab/jupyterlab/compare/v4.6.2...08c20a121297016a352f8f6f96aabd25b5703aab))

###### Bugs fixed

- Fix Shift-click cell selection after editor text selection [#19243](https://github.com/jupyterlab/jupyterlab/pull/19243) ([@MUFFANUJ](https://github.com/MUFFANUJ))
- Fix active cell prompt and source blink in notebook tools & prevent a memory leak [#19168](https://github.com/jupyterlab/jupyterlab/pull/19168) ([@MUFFANUJ](https://github.com/MUFFANUJ))
- Update the item positions when an item is removed from reactive toolbar [#19227](https://github.com/jupyterlab/jupyterlab/pull/19227) ([@brichet](https://github.com/brichet))
- Fix variable inspection, document autocomplete and variable inspect/render [#19234](https://github.com/jupyterlab/jupyterlab/pull/19234) ([@krassowski](https://github.com/krassowski))
- Show "starting" rather than "idle" status when changing kernel via `SessionContext.changeKernel()` [#19166](https://github.com/jupyterlab/jupyterlab/pull/19166) ([@Zsailer](https://github.com/Zsailer))

###### Maintenance and upkeep improvements

- Update Altair snapshot [#19204](https://github.com/jupyterlab/jupyterlab/pull/19204) ([@krassowski](https://github.com/krassowski))
- Switch pre-commit to `language: system` [#19193](https://github.com/jupyterlab/jupyterlab/pull/19193) ([@krassowski](https://github.com/krassowski))

###### Documentation improvements

- Update JEP 91 link to the new MyST docs URL [#19212](https://github.com/jupyterlab/jupyterlab/pull/19212) ([@jtpio](https://github.com/jtpio))

###### Contributors to this release

The following people contributed discussions, new ideas, code and documentation contributions, and review.
See [our definition of contributors](https://github-activity.readthedocs.io/en/latest/use/#how-does-this-tool-define-contributions-in-the-reports).

([GitHub contributors page for this release](https://github.com/jupyterlab/jupyterlab/graphs/contributors?from=2026-07-21&to=2026-08-10&type=c))

@brichet ([activity](https://github.com/search?q=repo%3Ajupyterlab%2Fjupyterlab+involves%3Abrichet+updated%3A2026-07-21..2026-08-10&type=Issues)) | @jtpio ([activity](https://github.com/search?q=repo%3Ajupyterlab%2Fjupyterlab+involves%3Ajtpio+updated%3A2026-07-21..2026-08-10&type=Issues)) | @krassowski ([activity](https://github.com/search?q=repo%3Ajupyterlab%2Fjupyterlab+involves%3Akrassowski+updated%3A2026-07-21..2026-08-10&type=Issues)) | @MUFFANUJ ([activity](https://github.com/search?q=repo%3Ajupyterlab%2Fjupyterlab+involves%3AMUFFANUJ+updated%3A2026-07-21..2026-08-10&type=Issues)) | @Zsailer ([activity](https://github.com/search?q=repo%3Ajupyterlab%2Fjupyterlab+involves%3AZsailer+updated%3A2026-07-21..2026-08-10&type=Issues))