Cannot change textColor of background events in fullcalendar

I am using fullcalendar.io v6 in my vue app with normal events and background events. However I want to change the textColor, which works with normal events perfectly but the background events doesn´t change unless I remove display: 'background'. How can I customize the textcolor of my background events?

 {    task_id: 2,    title: 'Test Time event',    start: '2024-06-10T15:00:00',    end: '2024-06-10T16:00:00',    display: 'background',    backgroundColor: '#ff9f89',    borderColor: '#ff9f89',     textColor: 'green'  }