For your explanation. It's hard to do it generally. There isn't problem to save UNDO stack into some form of binary file. Now imagine: 1. you edited and closed your file. PSpad will save undo stack. 2. your file will change in other application 3. you will open file back in PSPad. You have undo stack, but your file content is different. Undo stack is useless, cause it will do everything else than you await from it.
-- <http://forum.pspad.com/read.php?2,60535,60537> PSPad freeware editor http://www.pspad.com
