Unable to Save Widget State

Hi Folks,

I'm looking at how to interact with itkwidget's state in the jupyter notebook and jupyer lab. Although I can:

- open jupyter lab
- open a notebook with an ITK plotter in use
- run the cell to get the 3D widget rendered
- save close and reopen the notebook (without closing lab)
- the 3D widget still appears immediately.


But if I close jupyter lab completely, or kill the active kernel, then reopen it and the notebook, the 3D plot is not visible and I get a message from the extension that it cannot find the model.

In Jupyter lab, i have selected the "Save Widget State Automatically" setting which for ipywidgets serialises the model to the notebook metadata, so that widgets are re-rendered when the notebook is opened.


However, the itk widgets state is not saved.

In parallel, when using the classic notebook there are various controls in the Widgets menu allowing a user to save/download/embed widgets state and these do nothing for my notebook containing the ITKPlotter.

Is this because the itkwidget extension needs to implement something in order to support saving/serialisation of the state?