All other types of draft entities such as text and sketched lines can be related to the view. The only one Proe doesn't want to let me do is a datum that has been added to the drawing from Insert, Draft Datum in drawing mode.
Try creating a draft datum. Your creating an actual datum that shows up as a feature in the part your working on. Draft datums have no parametric qualities and do not show up in the part. They are like a line that you sketch in the drawing. They are only cosmetic.