SizeToContent bug

<ribbon:RibbonWindow x:Class="Sample.Application.SizeToContentBug"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:ribbon="http://schemas.actiprosoftware.com/winfx/xaml/ribbon"
    Title="SizeToContent bug"
    SizeToContent="WidthAndHeight"
    >
  <Button>A simple button</Button>
</ribbon:RibbonWindow>

namespace Sample.Application
{
    /// <summary>
    /// Interaction logic for SizeToContentBug.xaml
    /// </summary>

    public partial class SizeToContentBug : RibbonWindow
    {

        public SizeToContentBug()
        {
            InitializeComponent();
        }

    }
}