When using the separate tabs window in stack mode, sometime you can open more tabs than fit in the docked window. One possible solution is to add a vertical scrollbar to scroll through the windows:
The following style adds ScrollViewer with vertical scroll bar visibility set to Auto, i.e. it is visible only when tabs don’t fit without scrolling:
<Style TargetType="TabsStudio:TabsHost" BasedOn="{StaticResource DefaultTabsHostStyle}">
<Setter Property="Template">
<Setter.Value>
<ControlTemplate TargetType="{x:Type TabsStudio:TabsHost}">
<ScrollViewer HorizontalScrollBarVisibility="Disabled"
VerticalScrollBarVisibility="Auto"
Focusable="False">
<Grid>
<Rectangle Width="{TemplateBinding Width}"
Height="{TemplateBinding Height}"
Fill="{TemplateBinding Background}"/>
<ContentPresenter/>
</Grid>
</ScrollViewer>
</ControlTemplate>
</Setter.Value>
</Setter>
</Style>

