Marketpress Product Category Widget Drop Down Option

Hi,

I've installed Marketpress on the Grid Market Theme but it seems when you add the Product Category widget to the sidebar and choose "dropdown", whenever a user tries to click on a category from the dropdown menu, nothing happens.

It does the same thing on a different theme I tried it on too.

Any suggestions please as to show as it's difficult to have it set as hierarchy when you have lots of categories.

Thanks

Chrissy