In iCal, I add an event. I then set
alert, at the time of the event, Message with Sound, Basso.
Before upgrading to Mac OS Sierra, at the time of the event, I would get a pop-up banner in the Notifications area. (The banner would pop-up even if the Notifications panel was closed).
Now nothing happens. If I click on the Notifications panel, it's listed in the side bar, but it doesn't pop-up.
In System Preferences > Notifications, I have iCal set to Alerts. I've also made sure that Do not disturb is disabled.
How can I bring the pop-up banner back?