public CatrobatListViewWorker()
{
_verticalItemMargin = 0;
_reorderEnabled = false;
GroupingEnabled = true;
_dragging = CatrobatListViewDragStaus.NotDragging;
_draggingItem = null;
SmartSelectedItems = new ObservableCollection<object>();
SmartSelectedItems.CollectionChanged += SmartSelectedItems_CollectionChanged;
_autoScrollOldYValue = 0;
_rearrangeOldYValue = 0;
SelectionEnabled = false;
}