Scheduler - Event.partStart()

I have a schedule with the business hours hidden, so it shows only from 9am to 10pm.

So, when I add an event from 9pm to 10am, it was supposed to show a duration of 2 hours only, not 13 hours, because it's business hour.

That can be a problem if a user wants to drag the event, because it will show an event of 13 hours long.

Is there a way to fix it? Any method to help me with that?

Thanks!