WPF-XAML-从父样式调用嵌套样式的动画

我正在尝试将ItemsControl修改为具有水印，以指示掉入其中的内容的行为。

我在VisualBrush中使用一个Label来显示单词“ OR”作为ItemsControl的背景（控件将包含将与在一起的属性过滤器）。背景更改由ItemsControl上的IsMouseOver触发。

问题是这样的：如果我直接在Label中设置不透明度，则可以使我的VisualBrush（请参阅xaml）显示/消失，但是如果尝试为标签使用嵌套样式，则无法使Opacity进行动画处理。我尝试了几种方法都没有成功，因此很高兴收到关于我的错误的任何提示。

我已经包括（已注释掉）我尝试过的两个动画。我还尝试使用ColorAnimation在Label上设置前景，但未成功。

非常感谢Ian Carson

<ItemsControl x:Name="OrFilterItemsTarget"
              ItemsSource="{Binding Assets.OrFilters}"
              ItemTemplateSelector="{StaticResource FilterTargetTemplateSelector}"
              ItemContainerStyle="{StaticResource DraggableItemStyle}"
              BorderThickness="0,0,0,0.5"
              BorderBrush="DimGray"
              AllowDrop="True"
              IsHitTestVisible="True"
              Margin="0,2.95,15.934,77"
              HorizontalAlignment="Right"
              Width="105">
    <ItemsControl.Style>
        <Style TargetType="{x:Type ItemsControl}">
            <Style.Resources>
                <Style x:Key="LabelStyle"
                       TargetType="{x:Type Label}">
                    <Style.Resources>
                        <Storyboard x:Key="FadeUp">
                            <DoubleAnimationUsingKeyFrames BeginTime="00:00:00"
                                                          Storyboard.TargetProperty="Opacity"
                                                          FillBehavior="HoldEnd">
                                <SplineDoubleKeyFrame KeyTime="00:00:2"
                                                     Value="0.5" />
                            </DoubleAnimationUsingKeyFrames>
                            <!--<DoubleAnimation Storyboard.TargetProperty="Opacity"
                                             From="0" To="0.5"
                                             Duration="0:0:2" />-->
                        </Storyboard>
                        <Storyboard x:Key="FadeDown">
                            <DoubleAnimationUsingKeyFrames BeginTime="00:00:00"
                                                           Storyboard.TargetProperty="Opacity"
                                                           FillBehavior="Stop">
                                <SplineDoubleKeyFrame KeyTime="00:00:2"
                                                      Value="0" />
                            </DoubleAnimationUsingKeyFrames>
                            <!--<DoubleAnimation Storyboard.TargetProperty="Opacity"
                                             From="0.5" To="0"
                                             Duration="0:0:2" />-->
                        </Storyboard>
                    </Style.Resources>
                    <Style.Triggers>
                        <DataTrigger Binding="{Binding Path=IsMouseOver, ElementName=OrFilterItemsTarget}"
                                     Value="True">
                            <DataTrigger.EnterActions>
                                <BeginStoryboard Storyboard="{StaticResource FadeUp}" />
                            </DataTrigger.EnterActions>
                        </DataTrigger>
                        <DataTrigger  Binding="{Binding Path=IsMouseOver, ElementName=OrFilterItemsTarget}"
                                      Value="False">
                            <DataTrigger.EnterActions>
                                <BeginStoryboard Storyboard="{StaticResource FadeDown}" />
                            </DataTrigger.EnterActions>
                        </DataTrigger>
                    </Style.Triggers>
                </Style>
                <VisualBrush x:Key="FilterContentType"
                             AlignmentX="Center"
                             AlignmentY="Center"
                             Stretch="None">
                    <VisualBrush.Visual>
                        <Label Content="OR"
                               Foreground="DarkGray"
                               Style="{StaticResource LabelStyle}">
                        </Label>
                    </VisualBrush.Visual>
                </VisualBrush>
            </Style.Resources>
            <Style.Triggers>
                <Trigger Property="IsMouseOver"
                         Value="True">
                    <Setter Property="Background"
                            Value="{StaticResource FilterContentType}" />
                </Trigger>
                <Trigger Property="IsMouseOver"
                         Value="False">
                    <Setter Property="Background"
                            Value="Transparent" />
                </Trigger>
            </Style.Triggers>
        </Style>
    </ItemsControl.Style>
    <ItemsControl.ItemsPanel>
        <ItemsPanelTemplate>
            <WrapPanel Orientation="Horizontal"
                       Background="Transparent">
                <i:Interaction.Behaviors>
                    <ei:FluidMoveBehavior AppliesTo="Children"
                                          Duration="0:0:0.3">
                        <ei:FluidMoveBehavior.EaseY>
                            <BackEase EasingMode="EaseIn"
                                      Amplitude="0.1" />
                        </ei:FluidMoveBehavior.EaseY>
                    </ei:FluidMoveBehavior>
                </i:Interaction.Behaviors>
            </WrapPanel>
        </ItemsPanelTemplate>
    </ItemsControl.ItemsPanel>
</ItemsControl>