If you missed it the first time out, check out Ragavendra Prabhu's Application Settings FAQ, which documents some of the trickier points of this great Whidbey technology.

Of course, you might ask, "Why isn't this stuff in the documentation, genius?!" It's a fair cop. Some of it is. A lot of it isn't. I'm logging a bug against myself today, and will add this stuff to the docs in the next cycle.