Importing ipyleaflet causes accordion and tab widgets to fail to render

[tylere]

After importing ipyleaflet, the accordion and tab widgets fail to render. The behavior occurs in Colab, but not in JupyterLab.

Script to reproduce: https://colab.research.google.com/drive/1YsTuzrRwFWBNq2ADDN0R6FZCTHcA6Dpb?usp=sharing

[antoinedaurat]

I have the same issue: after enabling the custom widget manager, the manager can't render the Accordion and Tab widgets.
They both fail at the same line, when trying to get "titles" from their model:

I encountered similar issues outside of colab (Accordion widget not rendering titles) but a simple upgrade to the latest ipywidgets version solved it.
It seems to me, that upgrading the @jupyter-widget/* dependencies of the manager could do the trick here too.

If you'd like, I'd be happy to try to fix it and submit a PR.