how to make a row below each regular row in a DevExpress ASPxGridView to advertise a verbose data point

1. in the ASPxGridView tag put inline...
   PreviewFieldName="Whatever"
   ...and herein "Whatever" will be the the appropriate getsetter/property on the POCO for which a collection has been databound to the ASPxGridView.
2. in the Settings tag inside the ASPxGridView tag put inline...
   ShowPreview="True"