Editing code in an open tab during days sometimes you need to see the point of change what you have done yesterday. In the case I just clicks UNDO until reaches the version I need. Then I can copy some part which were updated later or copy whole text to compare with current version (after reaching it again with REDO). So while clicking UNDO or REDO I want to see a time mark of this very change.

I understand now what it looks like almost a wiki-like version management system. :) But it doesn’t need to save intermediate changes at disk actually. There’s pretty sure could be timestamp property in state change objects of the UNDO/REDO stack. I just want those timestamps reveal in the interface. (It’s my guess, I didn’t see NPP code, don’t know how it actually organized.)

Hope now I made it more clear. :^)

could explain in more detail?
Last saved edition means first change after saved state only, correct?
What do you mean by current state of history if UNDO/REDO is pressed?

Cheers
Claudia