I live in a 6 year old townhome condominium community so fixtures are new. The overflow drain in the tub in my guest bedroom does not function. It is there with an opening under the round metal gadget but water does not go in, down or out of the tub when filled to the brim. I have tried and so did another resident.

Is it possible that this is a "dummy" and only looks proper for inspection and passing code regulations? Or is this overflow not required?

Thank you