It's possible to register a script with the "RETURN" hotkey - I did this for an Auto-correct feature (viz http://forum.pspad.com/read.php?2,40634 )
Getting it to play nicely with other scripts might be a problem though. -- <http://forum.pspad.com/read.php?2,10651,41132> PSPad freeware editor http://www.pspad.com
