General help

I'm investigating the use of Tags in Moodle 3.2 and when configuring the Tags block, the help option for tagged items context states that it can be limited to tags present in the current course category, course or module (see below). I want to be able to select the current course category but that is not showing in the drop down. I only see System and the current module. I want students to be able to search on tags where tagged resources found by the search are in a defined category. I hope someone can help, thanks Anne.