Location field not shown on my form

I really hope this doesn't turn out to be something I'm doing wrong cause I've spent a couple hours trying to figure this one out.

I've got a customized Sales Order form doesn't display the Location field (or in our case, the "Sales Agent Location" field).

Here is a screenshot of the form settings:


And here is one of the form:


Anyone think of anything that would prevent it from displaying?  It's marked as mandatory yet I'm not setting it (can't see it!) but I can still save the form.  Just another clue that it's REALLY not there (not hiding or rendering problem)