The add to cart code is on this details page. The code consists of two parts, the first part is the server side code that is actually adding the item to your cart. The second part is the form that you see on the page with the add to cart button. When you apply the server behavior to the page you will add both of these parts. If you want to remove this functionality from the page you can either remove the two parts manually or you can remove the add to cart server behavior on the page. The div that is on the page holding the form will not be removed, just the form inside of it for the add to cart.