In the NSX Manager UI, browse to Security > Distributed Firewall > Category Specific Rules
Use a filter to locate a policy or a rule. In the filtered view, the Policy level options are disabled.
This is observed in both federation and standalone NSX deployments.
However, at the rule level edit options are available in a filtered view (NSX 4.1.0 onward)
NSX 3.2.4
NSX 4.x
This is an expected behavior. This was done to address the issue described in KB: https://knowledge.broadcom.com/external/article/317518
Editing of policies in a filtered view will be available in an upcoming NSX release.