ipywidgets "default.js:127 TypeError: Cannot read property 'emit' of undefined"

[So-Cool]

Describe the bug

An ipywidgets' button does not work through Thebe when embedded on a Jupyter Book page.
Pressing a button after launching Thebe gives the following error in the web browser's console:

default.js:127 TypeError: Cannot read property 'emit' of undefined
    at Object.output (manager.js:54)
    at e.onIOPub (services-shim.js:97)
    at t.KernelShellFutureHandler._handleIOPub (future.js:204)
    at async t.KernelShellFutureHandler.handleMsg (future.js:173)
    at async v._handleMessage (default.js:1038)
(anonymous) @ default.js:127
Promise.catch (async)
_onWSMessage @ default.js:124

To Reproduce

Steps to reproduce the behavior:

1. Embed an ipywidgets' button on a Jupyter Book page
2. Launch Thebe (via Live Code)
3. Click the button

For example, see this page with button widgets.

Expected behavior

Clicking the button should execute the connected Python function.

Environment

• Python Version [e.g. 3.7.1]: 3.7.10
• Package versions or output of jupyter-book --version:
  • jupyter-book 0.10.1
  • sphinx-thebe 0.0.8
• Operating System: Ubuntu 18.04.5 LTS

Additional context

N/A

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[moorepants]

Thanks. Ipywidgets has very limited functionality with thebe. Related issues are #111 and #226.

[moorepants]

We've just merged some fixes that improve ipywidget functionality. Can you test with the tip of the master branch to see if your issue is resolved?

[So-Cool]

Apologies for not acting upon this earlier, @moorepants. Everything appears to work now. Thanks so much!