Expander view

Question

i hav an expanderview.which wen clicked expands...the contents which are viewed wen expanded are horizontally scrollable...!! but the header header also scrolls...!! i dont want the header to scroll along with the content..please help !!  i hav mentioned the code below please help !! tghank you !


<toolkit:ExpanderView
Width="1800"
Header="{Binding TaskName, Mode=TwoWay}"
x:Name="taskNameExpander" Margin="5,10,5,10" Foreground="#FF677389" FontSize="24" VerticalAlignment="Top" HorizontalAlignment="Left"
ItemsSource="{Binding dateTime}"
ItemTemplate="{StaticResource CustomItemTemplate}">
<toolkit:ExpanderView.ItemsPanel>
<ItemsPanelTemplate >
<StackPanel Orientation="Horizontal" Width="Auto" ScrollViewer.HorizontalScrollBarVisibility="Visible" ScrollViewer.VerticalScrollBarVisibility="Disabled"/>
</ItemsPanelTemplate>
</toolkit:ExpanderView.ItemsPanel>
</toolkit:ExpanderView>
</ScrollViewer>