feature request for clearing widget state on Jupyter Lab

[cornhundred]

I would like to have a button on Jupyter Lab that clears widget state. Checking the "Save Widget State Automatically" option on Jupyter Lab saves widget state, but I often end up with widget state remaining from previously overwritten widgets (e.g. deleting the widget cell without properly closing the widget).

This issue originated on a previous issue: #2563

[jasongrout]

Such a command would I think just need to call the widget manager's clear_state method

ipywidgets/packages/jupyterlab-manager/src/manager.ts

Lines 406 to 410 in a311d75

	async clear_state(): Promise<void> {
	await super.clear_state();
	this._modelsSync = new Map();
	this.setDirty();
	}

[vidartf]

What happens if you have live widgets (in kernel, and with views on page), and clear the state, let syncing happen, then save state?

[cornhundred]

Hi @vidartf, what do you mean by

clear the state

Do you mean properly closing the widget?

[vidartf]

My question was kind of multiple questions in one:

1. What actually happens in this case when the widget manager's clear_state method is called?
2. What happens in classic notebook if you use the "clear state" menu entry when widgets are live (if you then save the state, is there anything in it)?
3. What would you expect to happen with state / live widgets in these cases (when a menu entry "Clear widget state" is clicked)?