I’m trying to create a curved surface within the zemax part designer. Whenever I expose a point on my 2D sketch the expose point parameter greys out on all the points in the sketch. I am unable to check or uncheck the box for any of the points. I would like to expose all 4 points in the 2D sketch. Any idea why I’m unable to expose all the points. 

*Here is an image of the sketch. The I cannot check the expose point.

*Here shows a point that was exposed but I’m unable to uncheck the box.