System > Event Calendar Settings allow you to specify which types of events display in System > Event Calendar. The default displays all available event types.
Event types include: Send Mail, Backup, Restore, Network Share, Network, DNS, Routing, Admin, Mail Server, Time Change, Hostname Change, LDAP, Certificate, VM, RADIUS, Login, Logout, System, Reboot, Job Alert, Shutdown, Backup, Restore, Firmware Upgrade, Operation Center, Scan Profile, Scan Policy and Object, Allow/Block List or White/Black List, and Job Details.
Moving an event into the Unapplied Event Types category will hide all instances of those events in the Event Calendar. Moving an event into the Applied Event Types category will restore these events to the calendar, including past events.
Events can be moved between the two categories by dragging and dropping them.