Our test site using Joomla 3.5.1, Multi language but only use DK, Storefront template version 3.20.1, Virtuemart 3.0.16, PHP Version 5.6.20.
I use Virtuemart product module - featured, news in the shop - on Virtuemart frontpage (held by MetaMod so module only shows up on vm frontpage) - position mainbody_top.
Modul is setup to show 3 products in one row but it shows 3 products in one column. It worked before I disabled use VM css in config to get product details page to display properly.
"solve one problem gives another - keeps us busy".
Our shop is only for registred shopper so I have pm you login details if you want to have a look.