public override Rectangle DateTimePickerGetDateArea (DateTimePicker dateTimePicker)
{
if (!RenderClientAreas ||
dateTimePicker.ShowUpDown)
return base.DateTimePickerGetDateArea (dateTimePicker);
VisualStyleElement element = VisualStyleElement.DatePicker.DateBorder.Normal;
if (!VisualStyleRenderer.IsElementDefined (element))
return base.DateTimePickerGetDateArea (dateTimePicker);
Graphics g = dateTimePicker.CreateGraphics ();
Rectangle result = new VisualStyleRenderer (element).GetBackgroundContentRectangle (g, dateTimePicker.ClientRectangle);
g.Dispose ();
result.Width -= DateTimePickerDropDownWidthOnWindowsVista;
return result;
}