Thanks for your answer, I actualy mean on the following page
http://zenoss.localhost:8080/zport/dmd/Events/evconsole
I am unable to add filters to the columns at the above url.
I know I can use filters at the page below but I actualy want it to change on the events page that is clickable from the dashboard.
http://zenoss.localhost:8080/zport/dmd/itinfrastructure#devices:.zport.dmd.Devices:events_grid