Cart is hidden when using radio buttons for attributes

[Ulukman]

Hi all,

 

On the product list page, "add to cart" button changes its style to visibility: hidden when using "Radio Button" or "Color Picker" for the attributes of product. When I choose any attribute (from radio buttons), "add to cart" button is shown again (visibility:visible)

 

When I use dropdown for attributes, "add to cart" is shown normally.

 

Can you please help me to find the reason why changing attribute types also changes the way the cart is shown. I suspect it is related to Ajax.

 

My prestashop version is 1.5.4.1

Thanks.