jumping ListBox

Hi!

I have a little problem creating a custom ListBox in Dec-CTP. To see
the problem, just paste the code below into XamlPad.

Problem: Everytime you select an item at the bottom of the ListBox, the
ScrollViewer jumps almost to the top
Setting CanContentScroll="true" in the Template solves the Problem, but
creates other problems in my application, so this solution doesn't help
me at all

Any tips from you guys how to solve this problem?

Michael

<Grid Name="root"
xmlns="http://schemas.microsoft.com/winfx/avalon/2005"
xmlns:x="http://schemas.microsoft.com/winfx/xaml/2005">
<Grid.Resources>
<Style x:Key="{x:Type ListBox}" TargetType="{x:Type ListBox}">
<Setter Property="DefaultStyleKey" Value="{x:Null}" />
<Setter Property="Background" Value="White" />
<Setter Property="BorderThickness" Value="1" />
<Setter Property="BorderBrush" Value="#aa000000" />
<Setter Property="Padding" Value="2" />
<Setter Property="ScrollViewer.HorizontalScrollBarVisibility"
Value="Auto" />
<Setter Property="ScrollViewer.VerticalScrollBarVisibility"
Value="Auto" />
<Setter Property="Template">
<Setter.Value>
<ControlTemplate TargetType="{x:Type ListBox}">
<Border
CornerRadius="4"
Background="{TemplateBinding Background}"
BorderBrush="{TemplateBinding BorderBrush}"
BorderThickness="{TemplateBinding BorderThickness}"
>
<ScrollViewer
CanContentScroll="false"
Margin="1"
HorizontalScrollBarVisibility="{TemplateBinding
ScrollViewer.HorizontalScrollBarVisibility}"
VerticalScrollBarVisibility="{TemplateBinding
ScrollViewer.VerticalScrollBarVisibility}"
Padding="{TemplateBinding Padding}"
>
<ItemsPresenter/>
</ScrollViewer>
</Border>
</ControlTemplate>
</Setter.Value>
</Setter>
<Style.Triggers>
<Trigger Property="IsEnabled" Value="false">
<Setter Property="Background" Value="#EEEEEE" />
</Trigger>
</Style.Triggers>
</Style>
<Style x:Key="{x:Type ListBoxItem}" TargetType="{x:Type
ListBoxItem}">
<Setter Property="BorderBrush" Value="Transparent" />
<Setter Property="BorderThickness" Value="1" />
<Setter Property="Template">
<Setter.Value>
<ControlTemplate TargetType="{x:Type ListBoxItem}">
<Border CornerRadius="3"
Background="{TemplateBinding Background}" BorderBrush="{TemplateBinding
BorderBrush}" BorderThickness="{TemplateBinding BorderThickness}"
Padding="{TemplateBinding Padding}">
<ContentPresenter Content="{TemplateBinding
Content}" ContentTemplate="{TemplateBinding ContentTemplate}"
ContentTemplateSelector="{TemplateBinding ContentTemplateSelector}"
HorizontalAlignment="Stretch" Name="ContentSite"
VerticalAlignment="{TemplateBinding VerticalContentAlignment}" />
</Border>
</ControlTemplate>
</Setter.Value>
</Setter>
<Style.Triggers>
<Trigger Property="IsSelected" Value="True">
<Setter Property="Background" Value="#eeF5F5FF" />
<Setter Property="BorderBrush" Value="Silver" />
<Setter Property="Foreground" Value="Black" />
</Trigger>
</Style.Triggers>
</Style>
</Grid.Resources>
<ListBox HorizontalAlignment="Center" Height="150">
<ListBoxItem>Test1</ListBoxItem>
<ListBoxItem>Test2</ListBoxItem>
<ListBoxItem>Test3</ListBoxItem>
<ListBoxItem>Test4</ListBoxItem>
<ListBoxItem>Test5</ListBoxItem>
<ListBoxItem>Test6</ListBoxItem>
<ListBoxItem>Test7</ListBoxItem>
<ListBoxItem>Test1</ListBoxItem>
<ListBoxItem>Test2</ListBoxItem>
<ListBoxItem>Test3</ListBoxItem>
<ListBoxItem>Test4</ListBoxItem>
<ListBoxItem>Test5</ListBoxItem>
<ListBoxItem>Test6</ListBoxItem>
<ListBoxItem>Test7</ListBoxItem>
<ListBoxItem>Test1</ListBoxItem>
<ListBoxItem>Test2</ListBoxItem>
<ListBoxItem>Test3</ListBoxItem>
<ListBoxItem>Test4</ListBoxItem>
<ListBoxItem>Test5</ListBoxItem>
<ListBoxItem>Test6</ListBoxItem>
<ListBoxItem>Test7</ListBoxItem>
<ListBoxItem>Test1</ListBoxItem>
<ListBoxItem>Test2</ListBoxItem>
<ListBoxItem>Test3</ListBoxItem>
<ListBoxItem>Test4</ListBoxItem>
<ListBoxItem>Test5</ListBoxItem>
<ListBoxItem>Test6</ListBoxItem>
<ListBoxItem>Test7</ListBoxItem>
</ListBox>
</Grid>