Gets an instance of the System.Web.UI.Design.SupportsPreviewControlAttribute class that is set to the default preview value. This field is read-only.
The SupportsPreviewControlAttribute.SupportsPreviewControl property of the SupportsPreviewControlAttribute.Default field is set to false.
Use the SupportsPreviewControlAttribute.IsDefaultAttribute method to determine whether the value for the SupportsPreviewControlAttribute.SupportsPreviewControl property is set to the default preview value.