Csharp 为什么我的用户界面对象移动到略低于实际目标

我正在制作一个UWP项目，当我在Windows上浏览我的设置应用程序时，我意识到每当我按下一个按钮时，就会有一条蓝线移动. 我想为我的项目用UWP重新制作它，因为它看起来很好. 但每当动画播放时，它都会在实际按钮下方移动几个100个EPX.

为什么？

XAML脚本:

<Page
    x:Class="Library.Views.MainMenuView"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:local="using:Library.Helpers"
    xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
    xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
    mc:Ignorable="d"
    Background="{ThemeResource ApplicationBackgroundBrush}">

    <Grid>
        <Border HorizontalAlignment="Left" MaxWidth="400" MinWidth="200" Width="Auto" Height="Auto" Background="{ThemeResource ControlBackgroundBrush}" BorderBrush="{ThemeResource ControlHoveredBorderBrush}" BorderThickness="1" CornerRadius="0,8,8,0" >
            <StackPanel x:Name="Buttons">
                    <Button x:Name="Home" Style="{StaticResource UIButtonStyle}" Width="300" Height="40" FontSize="20" HorizontalAlignment="Center" Margin="5,8,12,8" Click="Button_Click">
                        <StackPanel Orientation="Horizontal" VerticalAlignment="Center">
                            <Image Source="/Assets/HomeNoBGRes.png" Width="35" Height="30" Margin ="0,0,10,0" Stretch="Fill"/>
                            <TextBlock Text="Home" FontSize="20" Width="240"/>
                        </StackPanel>
                    </Button>
                    <Button x:Name="Projects" Style="{StaticResource UIButtonStyle}" Width="300" Height="40" FontSize="20" HorizontalAlignment="Center" Margin="5,8,12,8" Click="Button_Click">
                        <StackPanel Orientation="Horizontal" VerticalAlignment="Center">
                            <Image Source="/Assets/ProjectsNoBGRes.png" Width="30" Height="30" Margin ="0,0,10,0" Stretch="Fill"/>
                            <TextBlock Text="My Projects" FontSize="20" Width="240"/>
                        </StackPanel>
                    </Button>
                    <Border Background="{ThemeResource ControlHoveredBackgroundBrush}" Width="270" Height="5" CornerRadius="3" HorizontalAlignment="Center"/>
                    <Button x:Name="Documents" Style="{StaticResource UIButtonStyle}" Width="300" Height="40" FontSize="20" HorizontalAlignment="Center" Margin="5,8,12,8" Click="Button_Click">
                        <StackPanel Orientation="Horizontal" VerticalAlignment="Center">
                            <Image Source="/Assets/DocsNoBGRes.png" Width="30" Height="30" Margin ="0,0,10,0" Stretch="Fill"/>
                            <TextBlock Text="Documents" FontSize="20" Width="240"/>
                        </StackPanel>
                    </Button>
                    <Button x:Name="Paper" Style="{StaticResource UIButtonStyle}" Width="300" Height="40" FontSize="20" HorizontalAlignment="Center" Margin="5,8,12,8" Click="Button_Click">
                        <StackPanel Orientation="Horizontal" VerticalAlignment="Center">
                            <Image Source="/Assets/PaperNoBGRes.png" Width="30" Height="30" Margin ="0,0,10,0" Stretch="Fill"/>
                            <TextBlock Text="Paper" FontSize="20" Width="240"/>
                        </StackPanel>
                    </Button>
                </StackPanel>
        </Border>
        <Border x:Name="SelectionIndicator" Visibility="Collapsed" Background="{ThemeResource SystemAccentColor}" Height="30" Width="5" CornerRadius="3" HorizontalAlignment="Left" Margin="5,0,0,0"/>
    </Grid>
</Page>

和C#动画函数:

        private void Button_Click(object sender, RoutedEventArgs e)
        {
            if (SelectionIndicator.Visibility == Visibility.Collapsed) SelectionIndicator.Visibility = Visibility.Visible;

            if (sender is  Button clickedButton) 
            { 
                double indicatorLeft = clickedButton.TransformToVisual(Buttons).TransformPoint(new Point(0, 0)).Y;

                if (SelectionIndicator.RenderTransform is null || !(SelectionIndicator.RenderTransform is CompositeTransform)) SelectionIndicator.RenderTransform = new CompositeTransform();

                CompositeTransform transform = SelectionIndicator.RenderTransform as CompositeTransform;

                Storyboard storyboard = new Storyboard();
                DoubleAnimation moveAnimation = new DoubleAnimation
                {
                    To = indicatorLeft,
                    Duration = TimeSpan.FromSeconds(0.5),
                    EnableDependentAnimation = true,
                    EasingFunction = new CircleEase { EasingMode= EasingMode.EaseInOut },
                };

                Storyboard.SetTarget(moveAnimation, transform);
                Storyboard.SetTargetProperty(moveAnimation, "TranslateY");

                storyboard.Children.Add(moveAnimation);

                storyboard.Begin();
            }
        }

这是一张展示我的问题的图片:

我试着在边框上添加一个网格，因为这可能是因为它们不在同一个容器中，但不是.

提前谢谢！

(致版主:不要抹杀我对预付款的感谢，这些是为了感谢那些真正帮助我的人)