Issue with adding products in Field Service app (Odoo V18)

[Diemux]

Hi All,

First off, many, many thanks to OCA in maintaining and upgrading the Field Service App (and many more) to the latest Odoo versions. You guys rock!

I'm setting up our Odoo v18 and would like to use the Field Service app. I have installed all the related apps:
FS Stock, FS Sales, FS Sale stock, FS Accounting, FS Repair etc.

Most options within FS work without issues, I can (auto) create orders, input field etc. But somehow I can't seem to add products and or activities. The tabs do show me a form and a header but there is no option to add a line/product.

I don't get any errors when creating and/or saving a FS order.