Created Issue: Silverlight ChildWindow hangs when scrolling a DataGrid that uses a TimePicker in its CellTemplate [9842]

We're getting this problem only if the controls are hosted within a ChildWindow. If we don't use a TimePicker (but some other control in the CellTemplate) then it works fine.

We're using the April 2010 Toolkit for Silverlight 4.

Steps to reproduce:
1. Add enough items to the DataGrid so that a Scollbar appears (about twice as is displayed in the grid).
2. Select an item in the DataGrid.
3. Scroll up and down a few times using the scrollbar.
Result: The page goes blank.

I've attached a test project which exhibits the problem. Basically you need the following xaml to be displayed inside a ChildWindow:

<sdk:DataGrid ItemsSource="{Binding TestItems}" AutoGenerateColumns="False" SelectedItem="{Binding SelectedTestItem, Mode=TwoWay}">
<sdk:DataGrid.Columns>
<sdk:DataGridTemplateColumn Width="*">
<sdk:DataGridTemplateColumn.CellTemplate>
<DataTemplate>
<Grid Margin="5">
<Grid.ColumnDefinitions>
<ColumnDefinition Width="*"/>
</Grid.ColumnDefinitions>
<inputToolkit:TimePicker Grid.Column="0" Value="{Binding}" HorizontalAlignment="Center" />
</Grid>
</DataTemplate>
</sdk:DataGridTemplateColumn.CellTemplate>
</sdk:DataGridTemplateColumn>
</sdk:DataGrid.Columns>
</sdk:DataGrid>

If anyone knows of any workarounds I'd love to hear about it.