Inheritance: ESRI.ArcGIS.Desktop.AddIns.Extension
        //http://help.arcgis.com/en/sdk/10.0/arcobjects_net/componenthelp/index.html#/ArcMap_Element/001v000001s7000000/
        protected override void OnStartup()
        {
            s_extension = this;

            // Wire up events
            ArcMap.Events.NewDocument += ArcMap_NewOpenDocument;
            ArcMap.Events.OpenDocument += ArcMap_NewOpenDocument;
        }