我有ScrollViewer这样的设置：
<ScrollViewer x:Name="scroller"
Focusable="False"
HorizontalScrollBarVisibility="Auto"
VerticalScrollBarVisibility="Hidden">
当我将VerticalScrollBarVisibility从Hidden更改为Disabled时，ScrollViewer的高度从115变为107（使用Snoop确认）。
我什么也没改变。我很难过。我似乎无法弄清楚为什么会发生这种情况。
我试图在Kaxaml中重现它，但它不会发生。
仅供参考：我的具体例子是一个相当复杂的棱镜应用程序。
为什么VerticalScrollBarVisibility会导致ScrollViewer的高度缩小？ （并切断控件的底部。）
更新
在Chris W.建议之前我没有想到它，但这可能与我的App Wide ScrollViewer风格有关。我要测试一下，看看我是否可以用它来重复。在这里，如果比我更聪明的头脑可以更快地找到问题。 （这很长，但需要制作自定义外观：
<ResourceDictionary xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:Microsoft_Windows_Themes="clr-namespace:Microsoft.Windows.Themes;assembly=PresentationFramework.Aero"
xmlns:System="clr-namespace:System;assembly=mscorlib">
<Brush x:Key="ScrollBackground">#7F5F5F5F</Brush>
<Brush x:Key="ScrollForeground">#DADADA</Brush>
<Brush x:Key="ScrollDisabled">#E3E3E3</Brush>
<Color x:Key="ScrollHashMarksDark">#656565</Color>
<Color x:Key="ScrollHashMarksLight">#C2C2C2</Color>
<System:Double x:Key="HashSize">1</System:Double>
<Style TargetType="{x:Type ScrollViewer}">
<Setter Property="Template">
<Setter.Value>
<ControlTemplate TargetType="{x:Type ScrollViewer}">
<Grid x:Name="Grid" Background="{TemplateBinding Background}">
<Grid.ColumnDefinitions>
<ColumnDefinition/>
<ColumnDefinition Width="Auto"/>
</Grid.ColumnDefinitions>
<Grid.RowDefinitions>
<RowDefinition />
<RowDefinition Height="Auto"/>
</Grid.RowDefinitions>
<Rectangle x:Name="Corner" Grid.Column="1" Fill="{DynamicResource {x:Static SystemColors.ControlBrushKey}}" Grid.Row="1"/>
<ScrollContentPresenter x:Name="PART_ScrollContentPresenter" CanContentScroll="{TemplateBinding CanContentScroll}" CanHorizontallyScroll="False" CanVerticallyScroll="False" ContentTemplate="{TemplateBinding ContentTemplate}" Content="{TemplateBinding Content}" Margin="{TemplateBinding Padding}" />
<ScrollBar x:Name="PART_VerticalScrollBar" AutomationProperties.AutomationId="VerticalScrollBar" Cursor="Arrow" Grid.Column="1" Maximum="{TemplateBinding ScrollableHeight}" Minimum="0" Grid.Row="0" Visibility="{TemplateBinding ComputedVerticalScrollBarVisibility}" Value="{Binding VerticalOffset, Mode=OneWay, RelativeSource={RelativeSource TemplatedParent}}" ViewportSize="{TemplateBinding ViewportHeight}" Width="8"/>
<ScrollBar x:Name="PART_HorizontalScrollBar" AutomationProperties.AutomationId="HorizontalScrollBar" Cursor="Arrow" Grid.Column="0" Maximum="{TemplateBinding ScrollableWidth}" Minimum="0" Orientation="Horizontal" Grid.Row="1" Visibility="{TemplateBinding ComputedHorizontalScrollBarVisibility}" Value="{Binding HorizontalOffset, Mode=OneWay, RelativeSource={RelativeSource TemplatedParent}}" ViewportSize="{TemplateBinding ViewportWidth}" Height="8"/>
</Grid>
</ControlTemplate>
</Setter.Value>
</Setter>
</Style>
<Style x:Key="ScrollBarPageButton" TargetType="{x:Type RepeatButton}">
<Setter Property="OverridesDefaultStyle" Value="true"/>
<Setter Property="Background" Value="Transparent"/>
<Setter Property="Focusable" Value="false"/>
<Setter Property="IsTabStop" Value="false"/>
<Setter Property="Template">
<Setter.Value>
<ControlTemplate TargetType="{x:Type RepeatButton}">
<Rectangle Fill="{TemplateBinding Background}" Height="{TemplateBinding Height}" Width="{TemplateBinding Width}"/>
</ControlTemplate>
</Setter.Value>
</Setter>
</Style>
<Style x:Key="HorizontalThumb" TargetType="{x:Type Thumb}">
<Setter Property="Template">
<Setter.Value>
<ControlTemplate TargetType="{x:Type Thumb}">
<Grid>
<Grid.ColumnDefinitions>
<ColumnDefinition Width="4" />
<ColumnDefinition Width="4" />
<ColumnDefinition />
<ColumnDefinition Width="Auto"/>
<ColumnDefinition />
<ColumnDefinition Width="4" />
<ColumnDefinition Width="4" />
</Grid.ColumnDefinitions>
<Ellipse Grid.Column="0" Grid.ColumnSpan="2" Fill="{StaticResource ScrollForeground}" />
<Rectangle Grid.Column="1" Grid.ColumnSpan="5" Fill="{StaticResource ScrollForeground}" />
<!--Add in the hash bars (in the middle of the scrollbar)-->
<StackPanel Orientation="Horizontal" Grid.Column="3">
<Border Width="{StaticResource HashSize}" Margin="0,0,2,0" CornerRadius="30">
<Border.Background>
<LinearGradientBrush>
<GradientStop Offset="0" Color="{StaticResource ScrollHashMarksDark}"/>
<GradientStop Offset=".75" Color="{StaticResource ScrollHashMarksDark}"/>
<GradientStop Offset="1" Color="{StaticResource ScrollHashMarksLight}"/>
</LinearGradientBrush>
</Border.Background>
</Border>
<Border Width="{StaticResource HashSize}" Margin="0,0,2,0" CornerRadius="30">
<Border.Background>
<LinearGradientBrush>
<GradientStop Offset="0" Color="{StaticResource ScrollHashMarksDark}"/>
<GradientStop Offset=".75" Color="{StaticResource ScrollHashMarksDark}"/>
<GradientStop Offset="1" Color="{StaticResource ScrollHashMarksLight}"/>
</LinearGradientBrush>
</Border.Background>
</Border>
<Border Width="{StaticResource HashSize}" Margin="0" CornerRadius="30">
<Border.Background>
<LinearGradientBrush>
<GradientStop Offset="0" Color="{StaticResource ScrollHashMarksDark}"/>
<GradientStop Offset=".75" Color="{StaticResource ScrollHashMarksDark}"/>
<GradientStop Offset="1" Color="{StaticResource ScrollHashMarksLight}"/>
</LinearGradientBrush>
</Border.Background>
</Border>
</StackPanel>
<Ellipse Grid.Column="5" Grid.ColumnSpan="2" Fill="{StaticResource ScrollForeground}" />
</Grid>
</ControlTemplate>
</Setter.Value>
</Setter>
</Style>
<Style x:Key="VerticalThumb" TargetType="{x:Type Thumb}">
<Setter Property="Template">
<Setter.Value>
<ControlTemplate TargetType="{x:Type Thumb}">
<Grid>
<Grid.RowDefinitions>
<RowDefinition Height="4" />
<RowDefinition Height="4" />
<RowDefinition Height="*" />
<RowDefinition Height="Auto" />
<RowDefinition Height="*"/>
<RowDefinition Height="4" />
<RowDefinition Height="4" />
</Grid.RowDefinitions>
<Ellipse Grid.Row="0" Grid.RowSpan="2" Fill="{StaticResource ScrollForeground}" />
<Rectangle Grid.Row="1" Grid.RowSpan="5" Fill="{StaticResource ScrollForeground}" />
<!--Add in the hash bars (in the middle of the scrollbar)-->
<StackPanel Orientation="Vertical" Grid.Row="3">
<Border Height="{StaticResource HashSize}" Margin="0,0,0,2" CornerRadius="30">
<Border.Background>
<LinearGradientBrush>
<GradientStop Offset="0" Color="{StaticResource ScrollHashMarksDark}"/>
<GradientStop Offset=".75" Color="{StaticResource ScrollHashMarksDark}"/>
<GradientStop Offset="1" Color="{StaticResource ScrollHashMarksLight}"/>
</LinearGradientBrush>
</Border.Background>
</Border>
<Border Height="{StaticResource HashSize}" Margin="0,0,0,2" CornerRadius="30">
<Border.Background>
<LinearGradientBrush>
<GradientStop Offset="0" Color="{StaticResource ScrollHashMarksDark}"/>
<GradientStop Offset=".75" Color="{StaticResource ScrollHashMarksDark}"/>
<GradientStop Offset="1" Color="{StaticResource ScrollHashMarksLight}"/>
</LinearGradientBrush>
</Border.Background>
</Border>
<Border Height="{StaticResource HashSize}" Margin="0" CornerRadius="30">
<Border.Background>
<LinearGradientBrush>
<GradientStop Offset="0" Color="{StaticResource ScrollHashMarksDark}"/>
<GradientStop Offset=".75" Color="{StaticResource ScrollHashMarksDark}"/>
<GradientStop Offset="1" Color="{StaticResource ScrollHashMarksLight}"/>
</LinearGradientBrush>
</Border.Background>
</Border>
</StackPanel>
<Ellipse Grid.Row="5" Grid.RowSpan="2" Fill="{StaticResource ScrollForeground}" />
</Grid>
</ControlTemplate>
</Setter.Value>
</Setter>
</Style>
<Style TargetType="{x:Type ScrollBar}">
<Style.Resources>
<Style x:Key="ScrollBarGrid" TargetType="{x:Type Grid}">
<Setter Property="Background" Value="{StaticResource ScrollBackground}"/>
<Style.Triggers>
<DataTrigger Binding="{Binding RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type ScrollBar}}, Path=IsEnabled}" Value="False">
<Setter Property="Background" Value="{StaticResource ScrollDisabled}"/>
</DataTrigger>
</Style.Triggers>
</Style>
</Style.Resources>
<Setter Property="Stylus.IsPressAndHoldEnabled" Value="false"/>
<Setter Property="Stylus.IsFlicksEnabled" Value="false"/>
<Setter Property="Foreground" Value="{DynamicResource {x:Static SystemColors.ControlTextBrushKey}}"/>
<Setter Property="Width" Value="10"/>
<Setter Property="MinWidth" Value="10"/>
<Setter Property="Template">
<Setter.Value>
<ControlTemplate TargetType="{x:Type ScrollBar}">
<Grid x:Name="Bg" SnapsToDevicePixels="true" Style="{StaticResource ScrollBarGrid}">
<Grid.RowDefinitions>
<RowDefinition Height="0.00001*"/>
</Grid.RowDefinitions>
<Track x:Name="PART_Track" IsDirectionReversed="true" IsEnabled="{TemplateBinding IsMouseOver}" Grid.Row="1">
<Track.DecreaseRepeatButton>
<RepeatButton Command="{x:Static ScrollBar.PageUpCommand}" Style="{StaticResource ScrollBarPageButton}"/>
</Track.DecreaseRepeatButton>
<Track.IncreaseRepeatButton>
<RepeatButton Command="{x:Static ScrollBar.PageDownCommand}" Style="{StaticResource ScrollBarPageButton}"/>
</Track.IncreaseRepeatButton>
<Track.Thumb>
<Thumb Style="{DynamicResource VerticalThumb}" Microsoft_Windows_Themes:ScrollChrome.ScrollGlyph="VerticalGripper" Width="8"/>
</Track.Thumb>
</Track>
</Grid>
</ControlTemplate>
</Setter.Value>
</Setter>
<Style.Triggers>
<Trigger Property="Orientation" Value="Horizontal">
<Setter Property="Width" Value="Auto"/>
<Setter Property="MinWidth" Value="0"/>
<Setter Property="Height" Value="10"/>
<Setter Property="MinHeight" Value="10"/>
<Setter Property="Template">
<Setter.Value>
<ControlTemplate TargetType="{x:Type ScrollBar}">
<Grid x:Name="Bg" SnapsToDevicePixels="true" Style="{StaticResource ScrollBarGrid}">
<Grid.ColumnDefinitions>
<ColumnDefinition Width="0.00001*"/>
</Grid.ColumnDefinitions>
<Track x:Name="PART_Track" Grid.Column="1" IsEnabled="{TemplateBinding IsMouseOver}">
<Track.DecreaseRepeatButton>
<RepeatButton Command="{x:Static ScrollBar.PageLeftCommand}" Style="{StaticResource ScrollBarPageButton}"/>
</Track.DecreaseRepeatButton>
<Track.IncreaseRepeatButton>
<RepeatButton Command="{x:Static ScrollBar.PageRightCommand}" Style="{StaticResource ScrollBarPageButton}"/>
</Track.IncreaseRepeatButton>
<Track.Thumb>
<Thumb Microsoft_Windows_Themes:ScrollChrome.ScrollGlyph="HorizontalGripper" Style="{DynamicResource HorizontalThumb}" Height="8"/>
</Track.Thumb>
</Track>
</Grid>
</ControlTemplate>
</Setter.Value>
</Setter>
</Trigger>
<Trigger Property="IsEnabled" Value="False">
<Setter Property="Background" Value="Red"/>
</Trigger>
</Style.Triggers>
</Style>
</ResourceDictionary>