I’m using AvalonDock to develop a tool for internal use by our developers and QA. I am working on a custom version of the VS2010 style that is provided in the Themes. The style just didn’t function enough like VS2010 for me to be happy with it. I’ve made almost all the color and image changes and I just noticed that the tabs in the DocumentPane do not scroll like VS2010 when there are more tabs than can fit in the header area.
Since I have the complete style in my project I found the area where the styles are applied. I placed a ScrollViewer around the ad:DocumentTabPanel thinking I could somehow restyle the horizontal scrollbar so that there would be an arrow on the left and on the right of the tabs.
Is this possible?

Here is the style after my base modifications but without any modification to the scrollviewer:
<Style x:Key="{x:Type ad:DocumentPane}" TargetType="{x:Type ad:DocumentPane}">
<Setter Property="Background" Value="{DynamicResource {ComponentResourceKey {x:Type ad:DockingManager}, {x:Static ad:AvalonDockBrushes.DefaultBackgroundBrush}}}"/>
<Setter Property="FocusVisualStyle" Value="{x:Null}"/>
<Setter Property="Template">
<Setter.Value>
<ControlTemplate TargetType="{x:Type ad:DocumentPane}" >
<ControlTemplate.Resources>
<ContextMenu x:Key="DocumentsListMenu" StaysOpen="True" />
</ControlTemplate.Resources>
<Border
Background="{TemplateBinding Background}">
<Grid>
<Grid.RowDefinitions>
<RowDefinition Height="Auto"/>
<RowDefinition Height="*"/>
</Grid.RowDefinitions>
<Border x:Name="PART_Header"
Grid.Row="0"
Focusable="False"
>
<Grid>
<Grid.ColumnDefinitions>
<ColumnDefinition />
<ColumnDefinition Width="18"/>
</Grid.ColumnDefinitions>
<ScrollViewer HorizontalScrollBarVisibility="Hidden" VerticalScrollBarVisibility="Hidden" CanContentScroll="True">
<ad:DocumentTabPanel
x:Name="paneTabsPanel"
Panel.ZIndex ="1"
IsItemsHost="True"
TabItemStyle="{StaticResource CustomDocumentTabItemStyle}"/>
</ScrollViewer>
<Button x:Name="PART_ShowContextMenuButton"
Grid.Column="2"
Width="15" Height="15"
Style="{StaticResource PaneHeaderCommandStyle}">
<Image x:Name="ShowContextMenuIcon" Source="pack://application:,,,/Images/Dev2010/PinMenu.png" Width="13" Height="13" Stretch="None"/>
</Button>
</Grid>
</Border>
<Grid Grid.Row="1">
<Border
x:Name="topBorder"
Height="4"
Background="{DynamicResource {ComponentResourceKey {x:Type ad:DockingManager}, {x:Static ad:AvalonDockBrushes.DocumentHeaderBorder}}}"
CornerRadius="2,2,0,0"
VerticalAlignment="Top"
HorizontalAlignment="Stretch"
>
</Border>
<Border
x:Name="bottomBorder"
Height="4"
Background="{DynamicResource {ComponentResourceKey {x:Type ad:DockingManager}, {x:Static ad:AvalonDockBrushes.DocumentHeaderBorder}}}"
CornerRadius="0,0,2,2"
VerticalAlignment="Bottom"
HorizontalAlignment="Stretch"
>
</Border>
<ContentPresenter
Content="{Binding RelativeSource={RelativeSource TemplatedParent}, Path=SelectedItem.Content}"
Margin="0,4,0,4"
KeyboardNavigation.TabNavigation="Local"
KeyboardNavigation.DirectionalNavigation="Contained"
KeyboardNavigation.TabIndex="1"
/>
</Grid>
</Grid>
</Border>
<ControlTemplate.Triggers>
<Trigger Property="HasItems" Value="False">
<Setter Property="Visibility" Value="Hidden"/>
</Trigger>
<Trigger Property="ShowHeader" Value="False">
<Setter Property="Visibility" Value="Collapsed" TargetName="PART_Header" />
</Trigger>
<!--<DataTrigger Binding="{Binding Path=IsMainDocumentPane, RelativeSource={RelativeSource Self}}" Value="True">
<Setter Property="Source" Value="pack://application:,,,/Images/Dev2010/PinDockMenu.png" TargetName="ShowContextMenuIcon"/>
</DataTrigger>-->
<Trigger Property="ContainsActiveDocument" Value="True">
<Setter Property="Background"
Value="{DynamicResource {ComponentResourceKey {x:Type ad:DockingManager}, {x:Static ad:AvalonDockBrushes.DocumentHeaderBorderSelected}}}"
TargetName="topBorder"/>
<Setter Property="Background"
Value="{DynamicResource {ComponentResourceKey {x:Type ad:DockingManager}, {x:Static ad:AvalonDockBrushes.DocumentHeaderBorderSelected}}}"
TargetName="bottomBorder"/>
</Trigger>
<Trigger Property="ContainsActiveContent" Value="True">
<Setter Property="Background"
Value="{DynamicResource {ComponentResourceKey {x:Type ad:DockingManager}, {x:Static ad:AvalonDockBrushes.DocumentHeaderBorderSelectedActivated}}}"
TargetName="topBorder"/>
<Setter Property="Background"
Value="{DynamicResource {ComponentResourceKey {x:Type ad:DockingManager}, {x:Static ad:AvalonDockBrushes.DocumentHeaderBorderSelectedActivated}}}"
TargetName="bottomBorder"/>
</Trigger>
<EventTrigger RoutedEvent="Window.Loaded">
<BeginStoryboard>
<Storyboard>
<DoubleAnimation
Storyboard.TargetProperty="Opacity"
From="0" To="1" Duration="0:0:0.200" />
</Storyboard>
</BeginStoryboard>
</EventTrigger>
</ControlTemplate.Triggers>
</ControlTemplate>
</Setter.Value>
</Setter>
</Style>
I did something like this in the past, and found it easiest to hide the ScrollViewer’s ScrollBar, and manually scroll the content when two RepeatButtons are pressed.
The code I originally started with can be found here, but the basic idea is to overwrite the ScrollViewer’s template to look something like this: