Well Microsquish automatically updated my browser from IE 9 to IE 10, and now the return key doesn't do anything whether using the Quick-Reply or Advanced response boxes. I'm using the full WYSIWIG editor. I've also tried changing skins, which didn't matter. This also happens on GTT's sister site Workshop Addict; so I'm thinking it's a compatibility issue between vBulletin's forum software and IE 10. So now it looks like Tech Guy has another headache he probably doesn't want or need.