The fact that tab still does that just means that wherever the tab code is, isn't properly checking to see if there's a textbox highlighted. That should be easily fixed, although Keith would know where that is better. It's one for mantis.
Awesome that autocomplete and those other features are working, though! I would advise against ~ simply because a lot of keyboards don't have that -- German, for instance, lack that at all. And it's in an odd place on a variety of others.
Super cool, at any rate!