Userid can access the SYSVIEW SECURITY screen but can't do any changes.
Release : 16.0, 17.0
In this particular case, inability was caused by the fact that userid was added as ADMIN in the system configuration member but STC wasn't recycled.
When the user issue SECURITY cmd gets a similar screen as the below screenshot, a major indication is Stat: RO, which means read-only. The result of such a mode could be that someone with admin right already opened it and still doing something. The security definitions can be edited by one user at the same time. Another possible reason could be that userid was added as ADMIN into the system configuration member but SYSVIEW wasn't restarted, the definitions from the system configuration member were read during the startup, which means recycle is required.
Please see "How Administrators Are Defined" for additional details about adding additional Administrators.