# Modifying JupyterLab static JS

**URL:** <https://discourse.jupyter.org/t/modifying-jupyterlab-static-js/1761>\
**Category:** JupyterLab\
**Created:** [July 25, 2019, 9:46am UTC](https://discourse.jupyter.org/t/modifying-jupyterlab-static-js/1761 "2019-07-25T09:46:38Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![charlie-o](https://avatars.discourse-cdn.com/v4/letter/c/3ec8ea/32.png) [@charlie-o](https://discourse.jupyter.org/u/charlie-o)\
**Post date:** [July 25, 2019, 9:46am UTC](https://discourse.jupyter.org/t/modifying-jupyterlab-static-js/1761/1 "2019-07-25T09:46:38Z")

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Hi,

Sorry in advance if this is a stupid question!

I’ve been attempting to modify the JupyterLab JS to remove the “Overwrite file” dialog prompt.

To do this I modified the code in `packages/docregistry/context.js` - however, when I deploy this to our server and build it via `pip install .`, the old JS is still being served up.

Is this the right way to modify the JS, and if so what am I missing in the build process?

Thanks!

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**Author:** ![jasongrout](https://yyz1.discourse-cdn.com/flex031/user_avatar/discourse.jupyter.org/jasongrout/32/371_2.png) [@jasongrout](https://discourse.jupyter.org/u/jasongrout)\
**Post date:** [July 26, 2019, 11:22pm UTC](https://discourse.jupyter.org/t/modifying-jupyterlab-static-js/1761/2 "2019-07-26T23:22:02Z")

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You need to run jupyter lab with the `--dev-mode` flag to see your changes. See the developer instructions at [https://github.com/jupyterlab/jupyterlab/blob/b39a3441e1b32ba1f59b9ff580574e5950112a22/CONTRIBUTING.md#run-jupyterlab](https://github.com/jupyterlab/jupyterlab/blob/b39a3441e1b32ba1f59b9ff580574e5950112a22/CONTRIBUTING.md#run-jupyterlab)

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**Author:** ![charlie-o](https://avatars.discourse-cdn.com/v4/letter/c/3ec8ea/32.png) [@charlie-o](https://discourse.jupyter.org/u/charlie-o)\
**Post date:** [July 29, 2019, 8:14am UTC](https://discourse.jupyter.org/t/modifying-jupyterlab-static-js/1761/3 "2019-07-29T08:14:25Z")

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Ah… is there no way to build it in a way I can see my changes without dev-mode?