I'm able to connect via SSMS to Report Server using Windows Authentication -- the account has full SysAdmin rights within that instance of SQL server. I see the Jobs, Security and Shared Scheduled 'nodes' listed, and I can open Security to see 'Roles' and 'System Roles', and under each of those I can see the different roles. However, right-clicking to try to modify an existing role, create a new one, create a shared schedule, etc. -- no go. All options are greyed out and disabled.
I'm baffled. What could I be missing?