What is likely the cause of a permission being greyed out on the device tab of a role?

The reason the permission is greyed out on the device tab of a role is that it is already determined in the Overall Security tab, meaning it has been pre-set as allowed or denied. This design is intentional to maintain consistency and avoid conflicts between different sections of the security settings. If a permission is defined at a broader level, such as the Overall Security tab, it cannot be altered at the device level.

In practice, this ensures that users have a clear and predictable security protocol which prevents potential confusion arising from conflicting settings in different areas. When a permission is locked in this way, it reflects a design choice that streamlines administration by establishing certain overarching rules that apply universally across roles and devices.