public TreeViewItemAdorner(UIElement adornedElement)
: base(adornedElement)
{
var treeViewItem = adornedElement.ParentsUntil<TreeViewItem>();
var parentTreeViewItem = treeViewItem.ParentsUntil<TreeViewItem>();
_parentAdorner = parentTreeViewItem?.FindBehaviorInChildren<TreeViewItemDroppableBehavior>().Adorner;
_isParentFirstElement = parentTreeViewItem?.Items[0] == treeViewItem.DataContext;
IsHitTestVisible = false;
BorderBrush = Helpers.FindResource<SolidColorBrush>("DroppableAdornerBorderBrush");
BackgroundBrush = Helpers.FindResource<SolidColorBrush>("DroppableAdornerBackgroundBrush");
LineBrush = Helpers.FindResource<SolidColorBrush>("DroppableAdornerLineBrush");
}
