Feature Request: class setting per widget

This widget is fantastic and it’s one of my default installs.

One thing that I’d love to have is a field that lets me add a class to every instance of the TinyMCE widget.

Use case: of three TinyMCE widgets in a single sidebar, site operator would like each one to have it’s own background colour.

https://www.ads-software.com/plugins/black-studio-tinymce-widget/