Can't assign voucher to specific customer.

[prestandrew]

A customer made a payment which functions as a deposit. I am attempting to assign a voucher to that customer so that when they go to make the complete payment, it will come off of the total, but that customer is the only customer that DOES NOT come up when I start typing in the "Limit to a single customer" box. Every other customer I can get to show up, except this particular one.

 

Clicking on the magnifying glass does not bring up a search function, as I would expect. What entirely ridiculous thing am I missing here?

[prestandrew]

For anyone else who comes across this issue, I figured out what was going on. When the customer completed their transaction, they did so as a guest. I converted the account to a customer account and was able to apply the voucher.