Slightly off-topic, but a good thing to remember (that I learned the hard way troubleshooting this):

The /focus command will take a "unit_ID" argument, like "target", "party1", "targettarget" etc. It will also take a player's name, but only if that player is a person in your party or raid!

Try this on town on someone not in your party. You can type /focus someguynotinyourgroup and not have them selected, or you can target them and type /focus and they'll highlight right up nicely.