This project has two samples of same editor, GDScript version and C#.

The edtior has two state: Create, and Edit. It's similar to CRUD app, you can add to the list, remove item from and also edit. At the moment there is no functionality of changing index between item list, this is the first time I use Godot item list, so I'm not the best person here to show you how.

At the moment, there is nothing planned, but I think you can learn from this sample and make something even better that fits your design.

Good luck.