Just to reply a bit so you don't think I've disappeared or forgotten about you...

I was exploring this yesterday, and while it's straightforward to insert a new "thing" in the side panels and even make it look like the Quest panels with styles, making it
behave like a Quest panel is trickier, since that code is buried inside a jQuery "accordian" widget. I was struggling with it a bit last night without success, but I had a thought this morning that might work better - now I just need the time to try it, probably later this evening. So stay tuned and keep your fingers crossed.
As far as using the HTML tools to make a
permanent change - you can't. It's all temporary with the tools. They're handy for exploring the structure Quest has in place and making test changes, but you'll have to write some code (msg's, etc) to make the changes permanent within your game.