Certain capability not showing up.

Hello folks,

first of all I’d like to pint out that I really like Members. I used it successfully in quite a lot of WordPress projects.

Recently though I ran into a problem: I’m using the plugins “Events Calendar Pro” and “Event Tickets Plus” for selling tickets for courses with WooCommerce.
I wanted to create a new role for having access to the attendees’ information. The support team of the two plugins recommended to add the permissions to “tribe_manage_attendees” for this role. The problem is, this capability isn’t showing up in Members. What could be the reason?

For your hints many thanks in advance!