Some extra info:
When I set the height of the calendar to 100px then there is a scroll bar and he loads multiple events (not from the api, I have set the api that it adds 2 months before and after, to get more events, I should think that the calendar requests more events by itself, but it doesn't.).
But the height of the calendar is not 100px, it is around the 500/600px. But when I set the calendar to that height, it only shows 2 events (on 31 march), and there is no scroll bar. So there is nothing to scroll, but there are way more events. It seems that the calendar shows only the remaining events in march, and because of the height, there is no scrollbar.