A co-worker is trying to build a surface from some contours brought into a drawing (the contours are just polylines created by carlson in another drawing). He does have "Erase Previous Contour Entities" on, because there are contours created, that he does want removed, from his first couple attempts at this. When he goes to select the contours they're deleted prior to him selecting them. His computer froze up at one point after they were deleted, now he'll have to recreate them. He's wondering how he can prevent the erasure of the contours that were brought in from another drawing?