cell execution hangs after a session reconnect

[stevejpurves]

Describe the bug

context
When I am executing either a notebook or an embedded figure on a myst website that is connected to a remote jupyter session.

expectation
I expected to be able to run a notebook on a myst site and then refresh the page, reconnect and re-execute and for everything to work.

bug
But instead cell execution will not complete after reconnecting to the existing session. The cells spinners just keep running an there is no error message I the console.

problem
This is a problem for most people using a myst site, as it may work on first visit or isolated visits,m but on visits by the same person within the lifetime of the kernel/session they would hit this bug

Reproduce the bug

1. visit a myst website with notebook content, either hosted or in local dev
2. connect to a kernel and run all cells
3. refresh the page
4. connect to a kernel and run all cells or an individual cell
5. the [first] cell will stay busy

List your environment

No response

[stevejpurves]

I've experiences this on 2 binders, and think it is something to do with either unsuccessful reconnect to the session, or that the session is somehow left in a bad state after the first time around.

Hitting the "reset" button on figure or cell/notebook controls fixes the issue so it's definitely session related.

Need to test in other places including local and pay attention to versions. Perhaps recent changes to thebe introduced some unintended dep bumps or perhaps we need to upgrade there.