The current object must also have the EventMetric attribute defined. Only one field, property, or method in an object can have this value set true (it's false by default). If no item on an object is marked as the default, the number of events will be used as a default summary.
Requirements
Target Platforms: Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2