In the first version, I kept the familiar labels from some of the other BCX forms. I like it, but I don't feel like it's as efficient with space as it needs to be in such a small dialog. So for the second version, I took those out. I like it, but the thing I'm missing is the Calendar label -- it'd be nice to default to the "General Calendar," but maybe just labeling it like that is enough?
I'm going to start fleshing out the grid and a balloon in HTML now, but I'd love some feedback.