RE: What is the significance of reference field in a ...
Based on the value selected in a particular field,if you want to pop-up DFF segments, then reference field will be used.
eg:you have a field called Item. if you choose Computer as an Item, then in DFF segments you want to show Computer Brand name, Size. If you choose TV as an item , then in DFF you may want to show TV name,TV Color,TV Inches etc
in reference field, we enter :Item as Reference, then in context values,we enter the Item Values and then respective Segment names.