private static void OnConstrainToParentBoundsChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
        {
            MouseDragElementBehavior behavior = (MouseDragElementBehavior)d;

            behavior.UpdatePosition(behavior.X, behavior.Y);
        }
        private static void OnYChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
        {
            MouseDragElementBehavior behavior = (MouseDragElementBehavior)d;

            behavior.UpdatePosition(behavior.X, (float)e.NewValue);
        }