public void CopyDay(CalendarDay source)
 {
     SourceDay = source;
     if (SourceDay == null)
     {
         return;
     }
     DayCopied?.Invoke(null, null);
 }
 private void toolStripMenuItemCopy_Click(object sender, EventArgs e)
 {
     DayCopied?.Invoke(sender, new EventArgs());
 }