Quantity in cart - products with attributes not counted?

Folks! Having a wonderful time tweaking Zen-cart...

In my shop I have products in various colours, implemented as an attribute with radio buttons.

When I select an attribute and add the product to the cart, it is added to the cart nicely. On the product_info page, however, it is not counted in the cart. :no:
When I add the same product without attributes, it does get counted in the cart ("Quantity in cart: 1").

Is this a feature? Am I missing a setting, or should I dig some more in the source?
I am running version 1.3 and have verified this behaviour on several other sites, including sites featured on zen-cart.com.

This can be altered ...

The quantity in cart refers to the exact Product you are looking at ...

If you go to a Product directly that has attributes, it counts for products_id without attributes ...

If you go to a Product from the shopping cart ... it counts for the product_id with those defined attributes ...

In a future release of Zen Cart we will be modifying the option for how this count works to better fit different needs on different sites ...

ah, ok. thx for the speedy reply!