New Post: ChildWindow ComboBox

I'm having trouble with the ChildWindow in v2.0. If I have a combobox in the child window, it does not allow you to select different values.

With this example, ComboBoxInChildWindow does not work and ComboBoxInGrid does work.

<Window x:Class="WpfApplication2.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:sys="clr-namespace:System;assembly=mscorlib"
        xmlns:xctk="http://schemas.xceed.com/wpf/xaml/toolkit"
        Title="MainWindow" Height="350" Width="525">
    <Grid>
        <xctk:WindowContainer>
            <xctk:ChildWindow Visibility="Visible">
                <StackPanel>
                    <ComboBox Name="ComboBoxInChildWindow">
                        <ComboBox.Items>
                            <sys:String>1</sys:String>
                            <sys:String>2</sys:String>
                            <sys:String>3</sys:String>
                            <sys:String>4</sys:String>
                        </ComboBox.Items>
                    </ComboBox>
                </StackPanel>
            </xctk:ChildWindow>
        </xctk:WindowContainer>
        <ComboBox Name="ComboBoxInGrid" HorizontalAlignment="Right" VerticalAlignment="Top">
            <ComboBox.Items>
                <sys:String>1</sys:String>
                <sys:String>2</sys:String>
                <sys:String>3</sys:String>
                <sys:String>4</sys:String>
            </ComboBox.Items>
        </ComboBox>
    </Grid>
</Window>