Ubiquiti US-48 switches on UniFi. I can see connected mac/IP addresses, but can't match them up to specific ports? Am I missing something obvious here?

Looking at the switch through UniFi I see port 4 happily connected, and there are no complaints from any of the users. But port 4 is connecting at 100/10 Mbps and I want to know which machine out on the floor is being like this. (Inherited wiring is completely unlabeled so I can't just consult a chart and go to the drop like a civilized person).

The ports tab doesn't give me any information.

The clients tab shows a list of connected max addresses next to the related IP addresses, but doesn't tell me which device is on which port.

Is there something I'm missing in UniFi that will tell me which device is on which port?

And pressing my luck here, but when (if?) I can see which device is on which port, some of the devices that will be identified as IP phones with pass-through ethernet to the user's PC. Is there a way to identify the IP of the computer behind the phone on that specific switch port, or am I just SOL on that?