title: ScrollViewer.CanContentScroll not scrolling ItemsControl item by item
body: <p>I have an ItemControl on a ScrollViewer. I want to scroll item by item, now is scrolling pixel by pixel.</p>
  
  <pre><code>&lt;ScrollViewer Height="299" Margin="10,10,0,0" 
  HorizontalScrollBarVisibility="Visible" x:Name="Scroll"
                    VerticalAlignment="Top"  
                    Grid.Column="0" Grid.Row="1" 
                    PanningMode="HorizontalOnly" 
                    CanContentScroll="True"&gt;
          &lt;ItemsControl ItemsSource="{Binding RelativeSource={RelativeSource AncestorType=Window}, Path=Items, Mode=OneWay}"&gt;
              &lt;ItemsControl.ItemsPanel&gt;
                  &lt;ItemsPanelTemplate&gt;
                      &lt;VirtualizingStackPanel Orientation="Horizontal"/&gt;
                  &lt;/ItemsPanelTemplate&gt;
              &lt;/ItemsControl.ItemsPanel&gt;
              &lt;ItemsControl.ItemTemplate&gt;
                  &lt;DataTemplate&gt;
                      &lt;Border  Width="175" Height="64" Margin="0,0,16,16" HorizontalAlignment="Center" Focusable="False"&gt;
                          &lt;TextBlock Text="{Binding}" HorizontalAlignment="Center" VerticalAlignment="Center"/&gt;
                      &lt;/Border&gt;
                  &lt;/DataTemplate&gt;
              &lt;/ItemsControl.ItemTemplate&gt;
          &lt;/ItemsControl&gt;
      &lt;/ScrollViewer&gt;
  </code></pre>