Aha! I'm having the same problem but didn't know (until now) the precise cause. Very confusing and very frustrating at first until you track down that this is happening.
I think the problem is with Vista but agree that some sort of warning from PSPad would be essential. -- <http://forum.pspad.com/read.php?4,46504,47633> PSPad freeware editor http://www.pspad.com
