private void OnOwnerMouseLeftButtonDown(object sender, MouseButtonEventArgs e)
{
FinishDrag();
if (!ValidateSelectionDragSource(e.OriginalSource) || AdornerLayer.GetAdornerLayer(Owner) == null)
{
return;
}
Owner.AddHandler(UIElement.MouseMoveEvent, new MouseEventHandler(OnOwnerMouseMove), true);
Owner.LostMouseCapture += OnOwnerLostMouseCapture;
Owner.PreviewMouseUp += OnOwnerPreviewMouseLeftButtonUp;
Owner.LostFocus += OnOwnerLostFocus;
SelectionBoxAdorner = CreateSelectionBoxAdorner(Owner, SelectionBox, e.GetPosition(Owner));
}
