P: Undo History Brush

For me too, but not only for shapes. If I make a selection and I want to align layers centered the layers align to the center of the artboard and not the selection..

here is video link for it ... uploaded to my dropbox
https://www.dropbox.com/s/l24fd2grcj3...

ok I will

I'm not quite following your issue. Can you post a video of the behavior you're trying to describe?

Agree!

Would it be more intuitive if the History Brush was set to the last History State by default then? If any other History State is needed, it could be set manually as usual. This would be a lovely addition to Fade Last function as the history Brush could use various opacity to restore the image from the Last Step as needed?

You mean, if, when you activate the tool, it would target the last step as a source? I am wondering if the scripts events manager could not do that?

Fair enough.

What about the idea that there is separate tool (let's say it's the "Undo History Brush") that works exactly the same as "History Brush" - but sets the last step as History Source when chosen as set it back to previous History Step when another Tool is selected.

Unfortunately that wouldn't work too well -- because your first paint stroke becomes the undo state, and the next paint stroke wouldn't work as expected. You really need to target a specific history state, so it retains that source and doesn't keep changing sources.

Ok i see what your saying.