We are working with custom event renderer. There is an issue with events that are partially displayed on screen (i.e. the beginning of the event is hidden and only the end is visible). For these events, when a rerender is trigerred (by moving a flight for instance), then they are redrawn making custom rendering starting on the wrong position. I'm struggling to explain the behaviour. So I made 2 videos: one showing the issue on one of your example. One video on our tool so that you better understand how it impacts us. Thanks for your help.