Frequently Asked Questions (FAQ)

Below are some frequently asked questions. Click on a question to be directed to relevant information in our documentation or our GitHub repo.

General

• What is JupyterLab?

• What will happen to the classic Jupyter Notebook?

• Where is the official online documentation for JupyterLab?

• How can you report a bug or issue?

Usage

Notebook

My notebook is displaying cell outputs in an iframe. They are reset when scrolling back and forth.

Since JupyterLab v4, notebook rendering is optimized to display only the cells needed. This has side effects with iframes.

The current workaround is to set the settings Notebook => Windowing mode to defer or none. It will negatively impact the performance of JupyterLab when opening long notebooks and/or lots of files.

My notebook injects customized CSS that results in unexpected scrolling issues (e.g. it fails to scroll to the active cell).

Since JupyterLab v4, notebook rendering is optimized to display only the cells needed. It does not support changing element CSS margin (in particular for cells).

The workaround is to prefer injecting customized padding rather than margin. If you can not avoid changing the margins, you can set the settings Notebook => Windowing mode to defer or none. It will negatively impact the performance of JupyterLab when opening long notebooks and/or lots of files.

Tips and Tricks

• How do I start JupyterLab with a clean workspace every time?

Add 'c.ServerApp.default_url = '/lab?reset' to your jupyter_server_config.py. See How to create a jupyter_server_config.py for more information.

Development

• How can you contribute?

• How can you extend or customize JupyterLab?

• In the classic Notebook, I could use custom Javascript outputted by a cell to programmatically control the Notebook. Can I do the same thing in JupyterLab?

  JupyterLab was built to support a wide variety of extensibility, including dynamic behavior based on notebook outputs. To access this extensibility, you should write a custom JupyterLab extension. If you would like trigger some behavior in response to the user executing some code in a notebook, you can output a custom mimetype (MIME Renderer Plugins). We currently don’t allow access to the JupyterLab API from the Javascript renderer, because this would tie the kernel and the notebook output to JupyterLab and make it hard for other frontends to support it. If you have comments or suggestions on changes here, please comment on this issue.