Weird menu behavior in Social theme

I've got some experience with WordPress, but I'm no expert. I'm trying to simply get a menu displaying. For now, the menu will be the same whether user is logged in or guest.

The menu items that come with the template aren't useful to me. I wanted to add some and delete some items. I don't see a place to do that.

As such, I chose to create a custom menu and added a couple of pages to it. One I created, called "About US". The other is the default "Register" page.

When I change to the new menu under "Theme Locations", the menu disappears entirely. I thought this was something I screwed up, but when I installed a completely new wordpress site with a new database and new directory, I got exactly the same behavior. What am I missing?