New Post: PropertyGrid Categories closed by default

Hi,

I started a new project under VS2008 and .net 3.5. Here's my code :

<Grid>
        <xctk:PropertyGrid x:Name="_propertyGrid"/>
</Grid>

 public partial class Window1 : Window
    {
        public Window1()
        {
            InitializeComponent();

            _propertyGrid.SelectedObject = new Button() { Content = "TEST" };
        }
    }

Upon loading, all categories are expanded. I have tried with Toolkit v2.3 and v2.4.
You can see the result here : http://postimg.org/image/mtn8iyj5n/