Lock to prevent changes keeps unlocking itself in NIS Firewall....

For some reason, in the firewall window of NIS for Mac, when I click on the lock to prevent changes, the lock unlocks after approximately 3 seconds. Antivirus window stays locked as does Norton Confidential. 

Can someone explain, should I be concerned?

I noticed that I had the built in firewall enabled as well as the Norton firewall, I turned the OSX firewall off. This should not be relevant. Any info is of course appreciated.

 

Thx,

 

TWS