New Post: Problem with Propertygrid and fonts

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

In Code-Behind :
 public partial class MainWindow : Window
  {
    public MainWindow()
    {
      InitializeComponent();

      _propertyGrid.SelectedObject = new MyTest()
      {
        EditorFont = new Font()
        {
          MyFontFamily = new FontFamily("Stencil"),
          Size = 13
        }
      }; 
    }
  }

  public class MyTest
  {
    // Property in class
    private Font _editorFont;

    [Category( "Workspace" ),
    Description( "The font used for editing documents." ),
    DisplayName( "Editor Font" ),
    ExpandableObject()]
    public Font EditorFont
    {
      get
      {
        return _editorFont;
      }
      set
      {
        _editorFont = value;
      }
    }
  }

  [TypeConverter(typeof(FontConverter))]
  public class Font
  {
    public FontFamily MyFontFamily
    {
      get;
      set;
    }

    public int Size
    {
      get;
      set;
    }
  }

  public class FontConverter : TypeConverter
  {
    public FontConverter()
    {
    }

    public override bool CanConvertTo( ITypeDescriptorContext context, Type destinationType )
    {
      return ( destinationType == typeof( string ) )
        || base.CanConvertTo( context, destinationType );
    }

    public override bool CanConvertFrom( ITypeDescriptorContext context, Type sourceType )
    {
      return ( sourceType == typeof( string ) )
        || base.CanConvertFrom( context, sourceType );
    }

    public override object ConvertTo( ITypeDescriptorContext context, CultureInfo culture, object value, Type destinationType )
    {
      if( ( destinationType == typeof( string ) ) )
      {
        return "My Font";
      }
      return base.ConvertTo( context, culture, value, destinationType );
    }

    public override object ConvertFrom( ITypeDescriptorContext context, CultureInfo currentCulture, object value )
    {
      if( value != null && ( value is string ) )
      {
        return new Font();
      }
      return base.ConvertFrom( context, currentCulture, value );
    }
  }