Hello,
I am an account admin and I just enabled Differentiation Tags in the root account of our Canvas test and beta environments. I also confirmed that both the teacher and account admin role have all permissions enabled for Differentiaton Tags. Nevertheless, when I access the People tool in a course as an admin AND teacher, or just as a teacher, the Manage Tags button doesn't appear. I've tried suppressing all of our local customizations just in case, and that has no effect. Any ideas on why this might be happening?