I don't see any layered objects either, and if this is about z order for forms, IIRC Access does not support that for forms. If it is about controls, then I think this is neither a property or a method for any control. Methinks it is only doable via either application.runcommand or docmd.runcommand - in other words programmatically running ribbon commands. Even then, there is a send and a sendtoback command but there doesn't seem to be a sendtofront command. If one could get that to work, I imagine the only thing you can do is move things back in the layers. That could mean a whole bunch of sending back until the desired object ends up in the front. Probably not an issue with two controls, but certainly could be with several layers.
The more we hear silence, the more we begin to think about our value in this universe.
Paraphrase of Professor Brian Cox.