When I try to search with any term in the product search widget field, I always get this error message:
Warning: Illegal offset type in isset or empty in D:\Inetpub\webs\mydomain\wp-includes\post.php on line 1097
This line corresponds to this condition in post.php file:
if ( empty($wp_post_types[$post_type]) )
I have the last version of WordPress and Woocommerce installed.