I have the problem that for a custom new product type there are no taxes getting calculated and are always 0.
I found a solution here. It says there is a dropdown in the product details called Tax Class:
But there is no such field for me (on any product type). The attribute set is set to
Attribute Set "Default":
As you can see an attribute with name "tax_class_id" already exist in this attribute set, but why is it not showing?