Is it possible to have an Offline Lookup attached to a Single Line field? I can't get this to work in my dev environment in 10.3.1 and we have a customer that said they had it working in 10.2.1 but want to enable it in 10.3.1

In offline mode the lookup is disabled and in online mode it works. Only Drop Down fields allow me to use them in Offline mode.

UPDATE: The customer is thinking this may not have been a feature in 10.2.1. They may not have been using this form until 10.3.1