Recently I use XamDockManager and TabGroupPane with Prism 4.1 for silverlight 5 in v12.1, 

I add RegionManager.RegionName in TabGroupPane and need to add a TabGroupPaneRegionAdapter class. 

But I only found the abandoned project http://ncal.codeplex.com/

Anyone has some good suggestion?

some old code in codeplex: https://compositewpfcontrib.svn.codeplex.com/svn/Trunk/src/Extensions.Infragistics/Composite.Wpf.Infragistics/CompositeWPFContrib.Composite.Wpf.Infragistics/XamDockManager/Regions/TabGroupPaneRegionAdapter.cs

Bootstrapper


protected override RegionAdapterMappings ConfigureRegionAdapterMappings() {
            RegionAdapterMappings mappings = base.ConfigureRegionAdapterMappings();
            mappings.RegisterMapping(typeof(TabGroupPane),

             new TabGroupPaneRegionAdapter(Container.Resolve<IRegionBehaviorFactory>()));
            return mappings;
        } 

XAML

 <igDock:XamDockManager Grid.Row="2" x:Name="dockManager" >
            <igDock:DocumentContentHost>
                <igDock:SplitPane  VerticalAlignment="Stretch" HorizontalAlignment="Stretch">
                    <igDock:TabGroupPane Name="TabGroupPane1"
                                  prism:RegionManager.RegionName="{Binding TabRegion,Source={StaticResource RegionNames}}"

                                   prism:RegionManager.RegionContext="{Binding CurrentView}"

                                  VerticalAlignment="Top"/>

                </igDock:SplitPane>
            </igDock:DocumentContentHost>
 </igDock:XamDockManager>