Show attendee status (Declined event icon)

On Google Calendar, events where all participants declined the invitation receive an exclamation mark and a different background color. This is EXTREMELY helpful for optional events, as there is no need to click on the event and check every participant to see if the event should happen. Unfortunately, Morgen shows such events the same as everything else, which can lead to time lost joining a meeting and waiting for minutes until realizing that no one is joining (and having to check the calendar event manually).