Woocommerce wont show variations

Hi to all. I am really new to WordPress and Woocommerce and have some issues with product attributes. When for some product I add certian attribute and save the product, the attribute is saving OK. I use the attribute for variation, and is saving that OK too. But in select box on product front page is not showing. Further investigation show that array of all variations doesn’t contain the variation I added(in woocommerce variable.php in function get_terms(); ) . After that I noticed that for selected attribute the number of articles that is using selected attributes doesn’t change, it is still 0(in Products->Attributes->Some attribute, the far right column). When I manually change the record count in database from 0 to 1, the variations on product front page is shown. This is not happening on all attributes. If someone have any idea, I will be greatfull.