title: Lookup column in list not showing all possible fields
body: <p>I'm creating a list in SharePoint Designer - we'll call it ListA - with a lookup column referring to ListB, but not all of the columns in ListB are showing up in the column editor for the lookup column in ListA.  The column that isn't showing up is a simple drop-down selector.</p>
  
  <p>Any ideas as to why it's not showing up?</p>