Product List Yiels No Products

I've added the Product List widget to a sidebar, and asked for the category "workshops" to be displayed. (
It says No Products. I've tried different options, like "No Filter" or a Different Category name, always No Products.
The Widget Product Categories gives me my three categories, including workshops, which says it has 9 products.
Why aren't they showing? Can you help out?
Thanks in advance.