Checking the box to "only trust email from addresses in my safe senders ..." doesn' twork

When I go to Outlook Web Settings, Junk Mail, FILTERS, and check the box "only trust email from addresses in my safe senders and domains list and safe mailing lists" I then SAVE the setting.

All I need to do is go to another setting and then back to the one in question, and it remains UNCHECKED.

Is this a known issue? Can it not be set at all?