Upgrading extension for JupyterLab 4 compatibility

[BarbarossaWang]

Problem

Last week, JupyterLab release v4.0.0 that need upgrade existing extensions to use the new extesion systen and packaging.

Using current ipywidgets extesions in JupyterLab 4 that would throw Error displaying widget.

Proposed Solution

Check JupyterLab Extension Migration Guide.

[ibdafna]

Hey @BarbarossaWang welcome to the ipywidgets community!

Would you be able to share more context on this problem, perhaps with steps to reproduce your issue? Are you trying to build a custom widget? If you are trying to use ipywidgets in Jupyterlab 4 and are seeing an error, a set of steps to reproduce would be great. Thanks!

Bug report template: https://github.com/jupyter-widgets/ipywidgets/blob/main/.github/ISSUE_TEMPLATE/bug_report.md

[Yishai-s]

Hey @ibdafna,
I'm probably misunderstanding something, but I encountered a problem that may be the one @BarbarossaWang had.
With jupyterlab==4.0.1, ipywidgets==8.0.3, I start a jupyter lab and create a Tab:
import ipywidgets as widgets
widgets.Tab(children=(widgets.IntSlider(), widgets.IntSlider()), titles=('Tab1', 'Tab2'))

The Tab is indeed created, but it doesn't look right -

instead of how it is supposed to look (produced with jupyter notebook):

Thanks

[martinRenou]

@Yishai-s this has been fixed by #3787 and will be included in the next release

[Yishai-s]

Great,
Thanks!