How To Use the Four State CheckBoxes
To Enable the Four State checkboxes click on the preferences icon on the top right.
Place a check in the 'Enable Four State checkboxes' box.
Once this is enabled click 'save'. You now will be able to activate the locks by clicking in each field you wish the lock to appear. You will need to click 3 times to have a lock with no check mark in the box.
This feature should only be used sparingly. The most common area to use this feature is on the Antivirus page. You really don't want the virus to be delivered regardless of any other configuration settings or any exceptions that have been created.
Note: This feature is also good to use to not quarantine SURBL blocks, as there usually isn't any false positives with these and it will save room on the server.