Basedon原有样式对Template 进行重写，添加一个ScrollViewer
<ResourceDictionary xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
>
<Style x:Key="TabControlStyle" TargetType="{x:Type TabControl}" >
<Setter Property="Template" >
<Setter.Value>
<ControlTemplate TargetType="{x:Type TabControl}">
<Grid x:Name="templateRoot" ClipToBounds="True" SnapsToDevicePixels="True" KeyboardNavigation.TabNavigation="Local">
<Grid.ColumnDefinitions>
<ColumnDefinition x:Name="ColumnDefinition0"/>
<ColumnDefinition x:Name="ColumnDefinition1" Width="0"/>
</Grid.ColumnDefinitions>
<Grid.RowDefinitions>
<RowDefinition x:Name="RowDefinition0" Height="Auto"/>
<RowDefinition x:Name="RowDefinition1" Height="*"/>
</Grid.RowDefinitions>
<ScrollViewer HorizontalScrollBarVisibility="Auto" VerticalScrollBarVisibility="Auto" Style="{DynamicResource MahApps.Styles.ScrollViewer}">
<TabPanel x:Name="HeaderPanel" Background="Transparent" Grid.Column="0" IsItemsHost="True" Margin="0" Grid.Row="0" KeyboardNavigation.TabIndex="1" Panel.ZIndex="1"/>
</ScrollViewer>
<Line X1="0" X2="{Binding ActualWidth, RelativeSource={RelativeSource Self}}" Stroke="White" StrokeThickness="0.1" VerticalAlignment="Bottom" Margin="0 0 0 1" SnapsToDevicePixels="True"/>
<Border x:Name="ContentPanel" BorderBrush="{TemplateBinding BorderBrush}" BorderThickness="{TemplateBinding BorderThickness}" Background="{TemplateBinding Background}" Grid.Column="0" KeyboardNavigation.DirectionalNavigation="Contained" Grid.Row="1" KeyboardNavigation.TabIndex="2" KeyboardNavigation.TabNavigation="Local">
<ContentPresenter x:Name="PART_SelectedContentHost" ContentTemplate="{TemplateBinding SelectedContentTemplate}" Content="{TemplateBinding SelectedContent}" ContentStringFormat="{TemplateBinding SelectedContentStringFormat}" ContentSource="SelectedContent" Margin="0" SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}"/>
</Border>
</Grid>
<ControlTemplate.Triggers>
<Trigger Property="TabStripPlacement" Value="Bottom">
<Setter Property="Grid.Row" TargetName="HeaderPanel" Value="1"/>
<Setter Property="Grid.Row" TargetName="ContentPanel" Value="0"/>
<Setter Property="Height" TargetName="RowDefinition0" Value="*"/>
<Setter Property="Height" TargetName="RowDefinition1" Value="Auto"/>
</Trigger>
<Trigger Property="TabStripPlacement" Value="Left">
<Setter Property="Grid.Row" TargetName="HeaderPanel" Value="0"/>
<Setter Property="Grid.Row" TargetName="ContentPanel" Value="0"/>
<Setter Property="Grid.Column" TargetName="HeaderPanel" Value="0"/>
<Setter Property="Grid.Column" TargetName="ContentPanel" Value="1"/>
<Setter Property="Width" TargetName="ColumnDefinition0" Value="Auto"/>
<Setter Property="Width" TargetName="ColumnDefinition1" Value="*"/>
<Setter Property="Height" TargetName="RowDefinition0" Value="*"/>
<Setter Property="Height" TargetName="RowDefinition1" Value="0"/>
</Trigger>
<Trigger Property="TabStripPlacement" Value="Right">
<Setter Property="Grid.Row" TargetName="HeaderPanel" Value="0"/>
<Setter Property="Grid.Row" TargetName="ContentPanel" Value="0"/>
<Setter Property="Grid.Column" TargetName="HeaderPanel" Value="1"/>
<Setter Property="Grid.Column" TargetName="ContentPanel" Value="0"/>
<Setter Property="Width" TargetName="ColumnDefinition0" Value="*"/>
<Setter Property="Width" TargetName="ColumnDefinition1" Value="Auto"/>
<Setter Property="Height" TargetName="RowDefinition0" Value="*"/>
<Setter Property="Height" TargetName="RowDefinition1" Value="0"/>
</Trigger>
<Trigger Property="IsEnabled" Value="False">
<Setter Property="TextElement.Foreground" TargetName="templateRoot" Value="{DynamicResource {x:Static SystemColors.GrayTextBrushKey}}"/>
</Trigger>
</ControlTemplate.Triggers>
</ControlTemplate>
</Setter.Value>
</Setter>
</Style>
</ResourceDictionary>
