Closed Issue: Issue with the datagrid in a tab control using the twilight blue theme [3545]

I just upgraded my Silverlight 2 project to Silverlight 3. I attached the snippet of xaml that I am using below. What is happenning is that when data is loaded into the datagrid (approx 300 rows), I get very large amounts of white space between each row and when I try to scroll down using the scroll bar,
I occasionally get an application exception error. This happens on all of the datagrids on all of my tab controls. If I remove the theme from the tab controls, it works as expected.
Thanks

<twilightBlue:TwilightBlueTheme Background="{x:Null}">
<controls:TabControl Name="tbcontrol" SelectedIndex="0" Height="384" Grid.Row="1" Background="{x:Null}" Opacity="1" Foreground="{x:Null}" BorderBrush="{x:Null}" Width="716" HorizontalAlignment="Left" Canvas.Top="5" Canvas.Left="20" >
<controls:TabItem Visibility="Collapsed" ></controls:TabItem>
<controls:TabItem Background="#FF1666FF" Header="Winner List" BorderBrush="{x:Null}" Foreground="#FF000000">
<twilightBlue:TwilightBlueTheme>
<twilightBlue:TwilightBlueTheme.Background>
<RadialGradientBrush SpreadMethod="Reflect">
<GradientStop Color="#FFD8E4EC"/>
<GradientStop Color="#FF73C1F6" Offset="1"/>
</RadialGradientBrush>
</twilightBlue:TwilightBlueTheme.Background>

<Canvas x:Name="stkWinner" Height="Auto" HorizontalAlignment="Stretch" Margin="20,0,0,13" VerticalAlignment="Top" Background="{x:Null}" d:LayoutOverrides="Width">

<data:DataGrid x:Name="dgWinners" AutoGenerateColumns="False" GridLinesVisibility="None"
ItemsSource="{Binding Mode=OneWay}"
Height="224" Background="#FF5C7590" Width="685.822" Canvas.Left="-8.822" AlternatingRowBackground="#FF5C7590" Foreground="#FF120000" HorizontalAlignment="Stretch" Canvas.Top="57"/>
<RadioButton IsChecked="true" Content="Do Not Use Number Filters" GroupName="UseFilters" x:Name="NoFilterRadio" Height="17" Canvas.Left="383" Canvas.Top="289" Foreground="#FFFFFFFF"/>
<RadioButton Content="Use Number Filters" GroupName="UseFilters" x:Name="UseFilterRadio" Width="135" Height="17" Canvas.Left="383" Canvas.Top="306" Foreground="#FFFFFFFF"/>
<ProgressBar x:Name="LoadingWinnerList" Visibility="Collapsed" IsIndeterminate="True" Value="50" VerticalAlignment="Bottom" Width="116" Height="32" HorizontalAlignment="Right" Canvas.Top="289" Canvas.Left="561" />

<Button Content="Generate" Width="116" Click="Button_Click" x:Name="btnGetNumbers" Height="32" Canvas.Left="561" Canvas.Top="289"/>
<TextBlock HorizontalAlignment="Right" x:Name="txtFilteredCombo" VerticalAlignment="Bottom" Text="" TextWrapping="Wrap" d:LayoutOverrides="Width" Canvas.Top="305" Canvas.Left="-8.474"/>
<TextBlock Height="Auto" HorizontalAlignment="Right" x:Name="txtFilteredWinners" VerticalAlignment="Bottom" Width="Auto" Text="" TextWrapping="Wrap" Canvas.Top="285" Canvas.Left="-8.822"/>
<TextBlock HorizontalAlignment="Right" VerticalAlignment="Bottom" Text="The purpose of this tab is to display all of the winning numbers based on your filter criteria entered on the following tabs." TextWrapping="Wrap" Height="35" Width="482.992" Canvas.Left="-0.748" Canvas.Top="8"/>
</Canvas>
</twilightBlue:TwilightBlueTheme>
</controls:TabItem>
Comments: Bulk closing issues older than 2 years. Please reactivate if you still have this problem.