Sheet managers cannot see group field

Hi There,

Thanks for this great plugin I currently use for my school parent portal. I have bought the PTA SUS Group extension, however I cannot find a way to make the group field available to my sheet managers. As general admin I can see and adjust the group value in the backend. My sheet managers have a custom role to which I assigned the capabilities: manage_signup_sheets and manage_PTA. The Group field however doesn’t show up in the sheet management page nor the activity overview in the backend. It is shown correctly in the front end.

This way the extension is of no use for my site. Hopefully you can help me out.

Kind regards,
Remco van Rossum