Scheduler - HeaderRow Start at 23 o`clock

Yes, it's possible.

The StartDate must be set to the first day.

You need to use ShowNonBusiness="false" option. Then you will be able to hide individual time columns using BeforeTimeHeaderRender event handler.

Example:

protected void DayPilotScheduler1_BeforeTimeHeaderRender(object sender,
   DayPilot.Web.Ui.Events.BeforeTimeHeaderRenderEventArgs e)
{
  if (!e.IsColGroup && e.Start.Hour >= 3 && e.Start.Hour < 23)
  {
      e.Visible = false;
  }
}

You will need to adjust it a bit because this just hides cells between 3:00 and 23:00.

See also here:

http://www.daypilot.org/scheduler-hiding-non-business-hours.html

Let me know if this is not what you are trying to do.

Thanks a lot!
Hadn´t seen this solution. It works fine!!!

thx
Dennis