Created Issue: ListPicker does not work with selecteditem bound [10796]

My case is simple, and my xaml snippet is

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<StackPanel>
<toolkit:ListPicker Margin="10,10,4,10" Header="Birthplace" SelectedIndex="{Binding Source={StaticResource settings}, Path=Birthplace, Mode=TwoWay}">
<sys:String>City 1</sys:String>
<sys:String>City 2</sys:String>
<sys:String>City 3</sys:String>
<sys:String>City 4</sys:String>
<sys:String>City 5</sys:String>
</toolkit:ListPicker>
</StackPanel>