+ delete this.columnDrag.proxy.ghost;
+ delete this.columnDrag.dragData.ddel;
+ delete this.columnDrag.dragData.header;
+ this.columnDrag.destroy();
+ delete Ext.dd.DDM.locationCache[this.columnDrag.id];
+ delete this.columnDrag._domRef;
+
+ delete this.columnDrop.proxyTop;
+ delete this.columnDrop.proxyBottom;
+ this.columnDrop.destroy();
+ delete Ext.dd.DDM.locationCache["gridHeader" + this.grid.getGridEl().id];
+ delete this.columnDrop._domRef;
+ delete Ext.dd.DDM.ids[this.columnDrop.ddGroup];