That did the trick.
I don't quite understand why I should need to do this, however. It seems like "var chkUvbSecondary =Aliases....chkUvbSecondary;" ought to get the properties of the object at the moment it's invoked. Why would "Aliases....chkUvbSecondary" become stale? Are the properties bound at some earlier time?
In the form's OnLoad method, there will be changes to the relevant controls' properties wrt enablement and visibility. So are the properties of "Aliases....chkUvbSecondary" bound when the object first comes into existence and refreshed only if RefreshMappingInfo is invoked?
If that's so, then I guess objects should be refreshed whenever there's a possibility that the properties will have changed. It would be nice if there were a property such as Stale that would be true iff the properties had changed. Even better would be an option to refresh objects automatically as necessary when they're used.