Customising ticket fields - Company field missing

Hi, I’m customizing the ticket fields to our needs but the main Company field doesn’t show up as something that can be filled in when creating a ticket, despite all the visibility boxes being checked.  This is the lower one on the screenshot.  So I added a new field with same data source (Companies) (top one on the screenshot) and it shows up and works correctly.  Am I missing something obvious? I can’t remove the default company field as it’s a default field but it just doesn’t appear. Also when I drag and drop a new field with ‘pulldown’ type for population it just becomes a standard text field with search to fill out from data source.