I installed Woocommerce and then added Gravity Forms (together with the Woo GF Extension) to cope with complex pricing options. After adding a Gravity Form to a product page, the Woocommerce inbuilt Fancybox lightbox stopped working for the featured image (it was working before). If I remove the form, the lightbox works again.
I'm using a bare-bones custom theme with very few plugins.
Any ideas what might be causing the conflict, or how I might overcome it?