The only way to show a leader with iProperties on a part in which none of its edges are visible is to create a 3D Leader and then Retrieve Model Annotations. However those leaders are unable to be edited. While editing retrieved annotations would also be a useful feature, I need the ability to place a leader on the face of a part.
Typically, leaders not directly touching a line are shown with a dot or an oblique symbol instead of the arrow. This could be the default leader arrowhead for leaders placed on faces.