File attached.
The page with the Add to Cart behaviour is LED-Lights.php (attached).
1) It may be fine but it's contrary to the tutorial which is confusing.
2) When I bind something, let's say a database table field, and click "OK", it doesn't immediately update in the list of Bindings view. The only way I can check if it has binded correctly is to click "OK", and then open the Wizard again or click another option in the Bindings list.