I noticed that by the original contribution that the changes made to application_top.php in previous versions of this contribution
did as they were suppose to, but if you tried to add a product with attributes to the shopping cart it would only add the product
and redirect you to the shopping cart instead of the product_info page where you should be forced to select the attributes.
This uses the add to cart button instead of the buy_now button, if you do not like that you will have to make that change.

More...