public void select_item2()
        {
            _drop.Position = new Point(10, 20);
            _drop.Size     = new Vector2(30, 40);

            var target = new TestDropdownTarget("catpants");

            _drop.AddDropdownItem(new DropdownItem <TestDropdownTarget>(target, _drop)
            {
                Vertical   = VerticalAlignment.Top,
                Horizontal = HorizontalAlignment.Left,
                Size       = new Vector2(30, 40)
            });

            var target2 = new TestDropdownTarget("buttnuts");

            _drop.AddDropdownItem(new DropdownItem <TestDropdownTarget>(target2, _drop)
            {
                Vertical   = VerticalAlignment.Top,
                Horizontal = HorizontalAlignment.Left,
                Size       = new Vector2(30, 40)
            });

            _drop.SelectedItem = target2;

            _drop.SelectedDropdownItem.ShouldNotBeNull();
            _drop.SelectedItem.ShouldNotBeNull();
            _drop.SelectedItem.Text.ShouldBe("buttnuts");
        }
        public void add_null()
        {
            _drop.Position = new Point(10, 20);
            _drop.Size     = new Vector2(30, 40);

            var target = new TestDropdownTarget("catpants");

            _drop.AddDropdownItem(new DropdownItem <TestDropdownTarget>(target, _drop)
            {
                Vertical   = VerticalAlignment.Top,
                Horizontal = HorizontalAlignment.Left,
                Size       = new Vector2(30, 40)
            });

            _drop.AddDropdownItem(new DropdownItem <TestDropdownTarget>(null, _drop)
            {
                Vertical   = VerticalAlignment.Top,
                Horizontal = HorizontalAlignment.Left,
                Size       = new Vector2(30, 40)
            });

            _drop.SelectedItem = null;

            _drop.SelectedDropdownItem.ShouldBeNull();
            _drop.SelectedItem.ShouldBeNull();
        }