How to Undo Past Last Point

This is one of those things you do only once, thus easily forgotten. Did it for "my" machine, but now I'm a contractor using customer machine.

So how do I get rid of this annoying warning note, when I want to undo after saving a file:

You are about to undo past the last point this file was saved. Do you want to do this?

Open Terminal window and type:

defaults write com.apple.Xcode XCShowUndoPastSaveWarning NO

Restart Xcode and you're fine. Until next machine.