I have recreated two surfaces for my design, existing and proposed. I had used polylines for contours for in each surface. I tried labeling the contours but it will not let me select the contour itself. I then tried to make the contours to 3d polylines and again added them to the surface and rebuilt. I still am not allowed to label the contour since it doesn't let me select the polyline. I am able to select the surface however. What am I missing?