带有ScrollView的TextBlock使内容模糊

Question

我有一个带有文字的幻灯片转换。

代码：

SlideTransition slideTransition = new SlideTransition();
                slideTransition.Mode = SlideTransitionMode.SlideUpFadeIn;
                ITransition transition = slideTransition.GetTransition(TextBlockBorder);
                transition.Completed += delegate { transition.Stop(); 
                explanationText.Text = "";
                transition.Begin(); 

在XAML中：

<Border x:Name="TextBlockBorder" 
                                Margin="4,0,4,5" 
                                Height="200" 
                                VerticalAlignment="Bottom" 
                                HorizontalAlignment="Stretch" 
                                BorderThickness="1" 
                                BorderBrush="White" Background="#d5e1f3" 
                                Visibility="Collapsed">
                <ScrollViewer x:Name="ScrollViewer"
                              Margin="5"
                              HorizontalScrollBarVisibility="Disabled"
                              VerticalScrollBarVisibility="Auto">
                <StackPanel Orientation="Vertical" Margin="8">

                    <TextBlock Text="Explain : " />
                    <TextBlock x:Name="explainText"
                               Text="{Binding TextExplain}" />
                </StackPanel>
                </ScrollViewer>
            </Border>

这里当Sliding Up the text becomes blurr and then becomes normal，如何解决这个问题？这是一个错误吗？

我正在使用Windows Phone 8应用程序。