Disabling Class from Exception Tracker

I am using System Center 2012 SP1 and trying to disable all exceptions from the class(System.ArgumentException).

To set that in the .Net Performance Monitoring -->Exceptions Tracker I have All Namespaces set to Enabled and System.ArgumentException to Disabled. From the doc I understand should specify the NameSpace and ClassName and here Sysem is the NameSpace and the ArgumentException is the Class.

Still getting the exceptions thrown from this class. Is there anything misssing from the configuration.

Thanks