Wpf 为什么TabControl-DataTrigger-Storyboard的组合不起作用？

我在程序中遇到了某种绑定错误，我自己无法解释

我想设计一个

文本框

，这样，如果某个产品规格没有包含该值，它就会显示一个警告图标。当用户将光标悬停在图标上时，更详细的警告消息应出现在

装饰层中


正如你所看到的，控制是有效的，但我仍然有一个问题。为了描述我的问题，我将代码缩减到绝对最小值：

我的代码
App.xaml

<Application x:Class="WpfApplication3.App"
         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
         xmlns:ThemesAero="clr-namespace:Microsoft.Windows.Themes;assembly=PresentationFramework.Aero"
         StartupUri="MainWindow.xaml">
    <Application.Resources>
        <Style TargetType="{x:Type TextBox}" BasedOn="{StaticResource {x:Type TextBox}}">
            <Setter Property="Template">
                <Setter.Value>
                    <ControlTemplate TargetType="{x:Type TextBox}">
                        <Grid>
                            <Grid.ColumnDefinitions>
                                <ColumnDefinition />
                                <ColumnDefinition Width="Auto" />
                            </Grid.ColumnDefinitions>
                            <Grid.RowDefinitions>
                                <RowDefinition Height="22" />
                                <RowDefinition />
                            </Grid.RowDefinitions>
                            <ThemesAero:ListBoxChrome x:Name="Bd" BorderBrush="{TemplateBinding BorderBrush}" BorderThickness="{TemplateBinding BorderThickness}" Background="{TemplateBinding Background}" RenderMouseOver="{TemplateBinding IsMouseOver}" RenderFocused="{TemplateBinding IsKeyboardFocusWithin}" SnapsToDevicePixels="True">
                                <ScrollViewer x:Name="PART_ContentHost" SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}"/>
                            </ThemesAero:ListBoxChrome>
                            <Image Name="WarningIcon" Margin="5,0,0,0" Grid.Column="1" RenderOptions.BitmapScalingMode="HighQuality" Source="warning_256x256.png" />
                            <Border x:Name="InformationBorder" Background="#E1BA18" Margin="5,0,0,0" Grid.Row="1" Grid.ColumnSpan="2" Opacity="0" CornerRadius="1.5" IsHitTestVisible="False" MinHeight="24" MaxWidth="267" VerticalAlignment="Bottom" HorizontalAlignment="Left">
                                <TextBlock Text="This is some warning message." Foreground="White" Margin="8,3,8,3" TextWrapping="Wrap"/>
                            </Border>
                        </Grid>
                        <ControlTemplate.Triggers>
                            <DataTrigger Binding="{Binding ElementName=WarningIcon, Path=IsMouseOver}" Value="True">
                                <DataTrigger.EnterActions>
                                    <BeginStoryboard x:Name="fadeInStoryboard">
                                        <Storyboard>
                                            <DoubleAnimation Duration="00:00:00.15" Storyboard.TargetName="InformationBorder" Storyboard.TargetProperty="Opacity" To="1"/>
                                        </Storyboard>
                                    </BeginStoryboard>
                                </DataTrigger.EnterActions>
                                <DataTrigger.ExitActions>
                                    <StopStoryboard BeginStoryboardName="fadeInStoryboard"/>
                                    <BeginStoryboard x:Name="fadeOutStoryBoard">
                                        <Storyboard>
                                            <DoubleAnimation Duration="00:00:00.15" Storyboard.TargetName="InformationBorder" Storyboard.TargetProperty="Opacity" To="0"/>
                                        </Storyboard>
                                    </BeginStoryboard>
                                </DataTrigger.ExitActions>
                            </DataTrigger>
                        </ControlTemplate.Triggers>
                    </ControlTemplate>
                </Setter.Value>
            </Setter>
        </Style>
    </Application.Resources>
</Application>

<Window x:Class="WpfApplication3.MainWindow"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    Title="MainWindow" Height="350" Width="525">
    <Grid>
        <TabControl>
            <TabItem Header="Debug 1">
                <TextBox Height="80" Width="150" />
            </TabItem>
            <TabItem Header="Debug 2">
                <TextBox Height="80" Width="150" />
            </TabItem>
        </TabControl>
    </Grid>
</Window>

我试图解决什么问题？
当我阅读了一些关于如何修复此问题的建议解决方案时，我终于注意到以下所有触发器都工作正常：

<DataTrigger Binding="{Binding ElementName=WarningIcon, Path=IsMouseOver}" Value="True">
    <Setter TargetName="InformationBorder" Property="Opacity" Value="1" />
</DataTrigger>



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只有在
TabControl
中将
DataTrigger
与两个
Storyboard
一起使用时，才会发生此错误，但为什么？
我已经知道如何解决这个问题，所以我只对幕后发生的事情感兴趣

<DataTrigger Binding="{Binding ElementName=WarningIcon, Path=IsMouseOver}" Value="True">
    <Setter TargetName="InformationBorder" Property="Opacity" Value="1" />
</DataTrigger>

<Trigger SourceName="WarningIcon" Property="IsMouseOver" Value="True">
    <Trigger.EnterActions>
        <BeginStoryboard x:Name="fadeInStoryboard">
            <Storyboard>
                <DoubleAnimation Duration="00:00:00.15" Storyboard.TargetName="InformationBorder" Storyboard.TargetProperty="Opacity" To="1"/>
            </Storyboard>
        </BeginStoryboard>
    </Trigger.EnterActions>
    <Trigger.ExitActions>
        <StopStoryboard BeginStoryboardName="fadeInStoryboard"/>
        <BeginStoryboard x:Name="fadeOutStoryBoard">
            <Storyboard>
                <DoubleAnimation Duration="00:00:00.15" Storyboard.TargetName="InformationBorder" Storyboard.TargetProperty="Opacity" To="0"/>
            </Storyboard>
        </BeginStoryboard>
    </Trigger.ExitActions>
</Trigger>

<Trigger SourceName="WarningIcon" Property="IsMouseOver" Value="True">
    <Setter TargetName="InformationBorder" Property="Opacity" Value="1" />
</Trigger>