ItemsControl with ScrollViewer inside Template

ItemsControlWithScrollViewer.xaml

<Page
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:dd="urn:gong-wpf-dragdrop">
    <Grid>
        <ItemsControl x:Name="pnlBilder"
                      HorizontalAlignment="Center"
                      Width="300" Height="100"
                      dd:DragDrop.IsDragSource="True"
                      ScrollViewer.HorizontalScrollBarVisibility="Disabled"
                      ScrollViewer.VerticalScrollBarVisibility="Auto"
                      dd:DragDrop.IsDropTarget="True"
                      dd:DragDrop.DropScrollingMode="Both" >
            <ItemsControl.ItemTemplate>
                <DataTemplate>
                    <local:CoolView x:Name="ctrlView" Width="100" Height="100" />
                </DataTemplate>
            </ItemsControl.ItemTemplate>

            <ItemsControl.ItemsPanel>
                <ItemsPanelTemplate>
                    <WrapPanel />
                </ItemsPanelTemplate>
            </ItemsControl.ItemsPanel>

            <ItemsControl.Template>
                <ControlTemplate TargetType="{x:Type ItemsControl}">
                    <Border x:Name="Border"
                            SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}"
                            Background="{TemplateBinding Background}"
                            BorderBrush="{TemplateBinding BorderBrush}"
                            BorderThickness="{TemplateBinding BorderThickness}">
                        <ScrollViewer Margin="0"
                                      Focusable="False"
                                      Padding="{TemplateBinding Padding}"
                                      SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}"
                                      HorizontalScrollBarVisibility="{TemplateBinding ScrollViewer.HorizontalScrollBarVisibility}"
                                      VerticalScrollBarVisibility="{TemplateBinding ScrollViewer.VerticalScrollBarVisibility}"
                                      CanContentScroll="{TemplateBinding ScrollViewer.CanContentScroll}">
                            <ItemsPresenter SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}" />
                        </ScrollViewer>
                    </Border>
                    <ControlTemplate.Triggers>
                        <Trigger Property="IsEnabled" Value="False">
                            <Setter TargetName="Border" Property="Background" Value="Gray" />
                            <Setter TargetName="Border" Property="BorderBrush" Value="Silver" />
                        </Trigger>
                    </ControlTemplate.Triggers>
                </ControlTemplate>
            </ItemsControl.Template>
        </ItemsControl>
    </Grid>
</Page>