Adam,
After looking at your screenshots, it seems that the Region on the page is different than the Region you are setting in the Change action. On your page, Region is a drop down, which means it is either an attribute of type enumeration or a reference. However, in your Change action, Region is an attribute of type string. So the attribute you are setting to empty is not displayed on your page (or maybe not in your screenshot).
Hope that helps,
Mike
Thanks. Mike. That fixed it. I am clearly having a learning curve in converting from database foreign keys to associations.