Suggest Painter make available a history panel (like Photoshop) that displays each item done.
Why? Because hard to guess how many un-do's or re-do's via keyboard shortcuts. And working from the menu...the info is there but only one item at a time. Too tedious to manage a list from current limited info.
The history list could be simply the menu as a longer list; say last 20 steps...or make it an option for user choice of how many steps to show.
Or could be a panel with adjustable height so user can reveal a long or short list.
The data is already available in a list....only need to code how to display; and making a menu list longer is easy peasy.
Would make user effort for undo and redo much easier.
Hi.It may not be what you're looking for, but I often use the Clone Source panel as a history panel instead.
I leave a snapshot in the clone source when I want to keep a difference before a process that may possibly fail. You have to register them manually, but they have good visibility with thumbnails, and as long as you save them in RIF format, they won't be lost when you close the file. Convenient!
You are correct, a good idea, but not what I was suggesting to have a step by step un-do, and ability to go back many steps and re-do, step by step, or many steps.