Problem with selecting variations in Up-sells

Hi there,

I have installed and set-up the plug-in on one of my websites, but an error occurs. I have added up-sells to several products and it all works fine, except for one thing:

When you click add-to-cart on a product, the up-sells menu appears with several variable products. But when you try to select a variation and add it to your cart, it says “Please select a variation”. Then when you select a variation, it works fine. But you have to select a variation twice before it works.

Can you fix this?

Kind regards,
Herbert

P.s. if you want log-in information, what e-mail address can I use?