bug#40571: 28.0.50; Error displaying entry in customize group

[Štěpán Němec]

On Sun, 12 Apr 2020 02:37:53 -0700
Leo Alekseyev wrote:

> Using the latest version of emacs-ipython-notebook package and
> attempting to customize variables using M-x customize-group ein results
> in an error and corrupted custom buffer. This configuration works fine
> on 26.3

Did you try investigating the 3rd party package first?

There are instructions for reporting issues in their FAQ:

  https://github.com/millejoh/emacs-ipython-notebook#FAQ

In particular:

  Note EIN is tested only for released GNU Emacs versions 25.1 and
  later. Pre-release versions are unlikely to work.

You're also using some other 3rd party packages. Trying to strip those
down to a minimal reproducible recipe is more likely to get you useful
results. See (info "(emacs) Checklist")

-- 
Štěpán