The add button on the pick dialog does not work for me in either Firefox or IE. The search looks for a match on username, name, or email address. It will find first name or last name, but whole matches only, not substrings. Also, users can choose to hide their name and/or email address; so that is why you did not find Doug.
I have already put in a request with Jive to add substring searching and will create a ticket to have them fix the add button.