The DisplayTitle property returns either the current value of the base Title property or, if the control has no title, a calculated value. The calculated value consists of a localizable resource string for untitled controls. In the cases where no value is assigned to the Title property, the value of the DisplayTitle property differs from the Title property.
Because the DisplayTitle property is designed to be a read-only, calculated property to get the actual current value of the displayed title at run time, do not attempt to use this property to set a title for an EditorPart control. To set a title, use the base Title property.