XamDockManager–An Updated Prism Region Adapter

    private IRegion _region;
    private TabGroupPane _regionTarget;
    private XamDockManager _parentDockManager;

    public TabGroupPaneRegionAdapter(IRegionBehaviorFactory regionBehaviorFactory)
        : base(regionBehaviorFactory)
    {
    }

    protected override void Adapt(IRegion region, TabGroupPane regionTarget)
    {
        if (regionTarget.ItemsSource != null)
            throw new InvalidOperationException("ItemsSource property is not empty. This control is being associated with a region, but the control is already bound to something else. If you did not explicitly set the control's ItemSource property, this exception may be caused by a change in the value of the inherited RegionManager attached property.");

        _region = region;
        _regionTarget = regionTarget;
        _parentDockManager = XamDockManager.GetDockManager(regionTarget);

        SynchronizeItems();

        region.Views.CollectionChanged += Views_CollectionChanged;
    }

    protected override void AttachBehaviors(IRegion region, TabGroupPane regionTarget)
    {
        base.AttachBehaviors(region, regionTarget);

        if (!region.Behaviors.ContainsKey(TabGroupPaneRegionActiveAwareBehavior.BehaviorKey))
            region.Behaviors.Add(TabGroupPaneRegionActiveAwareBehavior.BehaviorKey, new TabGroupPaneRegionActiveAwareBehavior { HostControl = regionTarget });
    }

    protected override IRegion CreateRegion()
    {
        return new SingleActiveRegion();
    }

    void Views_CollectionChanged(object sender, NotifyCollectionChangedEventArgs e)
    {
        if (e.Action == NotifyCollectionChangedAction.Add)
        {
            //we want to add them behind any previous views that may have been manually declare in XAML or injected
            int startIndex = e.NewStartingIndex;
            foreach (object newItem in e.NewItems)
            {
                ContentPane contentPane = PrepareContainerForItem(newItem);

                if (_regionTarget.Items.Count != startIndex)
                    startIndex = 0;

                _regionTarget.Items.Insert(startIndex, contentPane);
            }
        }
        else if (e.Action == NotifyCollectionChangedAction.Remove)
        {
            IEnumerable<ContentPane> contentPanes = _parentDockManager.GetPanes(PaneNavigationOrder.VisibleOrder);
            foreach (ContentPane contentPane in contentPanes)
            {
                if (e.OldItems.Contains(contentPane) || e.OldItems.Contains(contentPane.Content))
                    contentPane.ExecuteCommand(ContentPaneCommands.Close);
            }
        }
    }

    /// <summary>
    /// Takes all the views that were declared in XAML manually and merges them with the region.
    /// </summary>
    private void SynchronizeItems()
    {
        if (_regionTarget.Items.Count > 0)
        {
            foreach (object item in _regionTarget.Items)
            {
                PrepareContainerForItem(item);
                _region.Add(item);
            }
        }
    }

    /// <summary>
    /// Prepares a view being injected as a ContentPane
    /// </summary>
    /// <param name="item">the view</param>
    /// <returns>The injected view as a ContentPane</returns>
    protected virtual ContentPane PrepareContainerForItem(object item)
    {
        ContentPane container = item as ContentPane;

        if (container == null)
        {
            container = new ContentPane();
            container.Content = item; //the content is the view being injected
            container.DataContext = ResolveDataContext(item); //make sure the dataContext is the same as the view. Most likely a ViewModel
            container.SetValue(IsGeneratedProperty, true); //we generated this one
            CreateDockAwareBindings(container);
        }

        container.CloseAction = PaneCloseAction.RemovePane; //make it easy on ourselves and have the pane manage removing itself from the XamDockManager
        container.Closed += Container_Closed;

        return container;
    }

    /// <summary>
    /// Executes when a ContentPane is closed.
    /// </summary>
    /// <remarks>Responsible for removing the ContentPane from the region, any event handlers, and clears the content as well as any bindings from the ContentPane to prevent memory leaks.</remarks>
    /// <param name="sender"></param>
    /// <param name="e"></param>
    void Container_Closed(object sender, Infragistics.Windows.DockManager.Events.PaneClosedEventArgs e)
    {
        ContentPane contentPane = sender as ContentPane;
        if (contentPane != null)
        {
            contentPane.Closed -= Container_Closed; //no memory leaks

            if (_region.Views.Contains(contentPane)) //we are dealing with a ContentPane directly
                _region.Remove(contentPane);

            var item = contentPane.Content; //this view was injected and set as the content of our ContentPane
            if (item != null && _region.Views.Contains(item))
                _region.Remove(item);

            ClearContainerForItem(contentPane); //reduce memory leaks
        }
    }

    /// <summary>
    /// Checks to see if the View or the View's DataContext (Most likely a ViewModel) implements the IDockAware interface and creates the necessary data bindings.
    /// </summary>
    /// <param name="container"></param>
    void CreateDockAwareBindings(ContentPane contentPane)
    {
        Binding binding = new Binding("Header");

        //let's first check the view that was injected for IDockAware
        var dockAwareContent = contentPane.Content as IDockAware;
        if (dockAwareContent != null)
            binding.Source = dockAwareContent;

        //fall back to data context of the content pane.
        var dockAwareDataContext = contentPane.DataContext as IDockAware;
        if (dockAwareDataContext != null)
            binding.Source = dockAwareDataContext;

        contentPane.SetBinding(ContentPane.HeaderProperty, binding);
    }

    /// <summary>
    /// Sets the Content property of a generated ContentPane to null.
    /// </summary>
    /// <param name="contentPane">The ContentPane</param>
    protected virtual void ClearContainerForItem(ContentPane contentPane)
    {
        if ((bool)contentPane.GetValue(IsGeneratedProperty))
        {
            contentPane.ClearValue(ContentPane.HeaderProperty); //remove any bindings
            contentPane.Content = null;
        }
    }

    /// <summary>
    /// Finds the DataContext of the view.
    /// </summary>
    /// <param name="item"></param>
    /// <returns></returns>
    private object ResolveDataContext(object item)
    {
        FrameworkElement frameworkElement = item as FrameworkElement;
        return frameworkElement == null ? item : frameworkElement.DataContext;
    }
}

    XamDockManager _parentDockManager;

    TabGroupPane _hostControl;
    public DependencyObject HostControl
    {
        get { return _hostControl; }
        set { _hostControl = value as TabGroupPane; }
    }

    protected override void OnAttach()
    {
        _parentDockManager = XamDockManager.GetDockManager(_hostControl);
        if (_parentDockManager != null)
            _parentDockManager.ActivePaneChanged += DockManager_ActivePaneChanged;

        Region.ActiveViews.CollectionChanged += ActiveViews_CollectionChanged;
    }        

    void DockManager_ActivePaneChanged(object sender, RoutedPropertyChangedEventArgs<ContentPane> e)
    {
        if (e.OldValue != null)
        {
            var item = e.OldValue;

            //are we dealing with a ContentPane directly
            if (Region.Views.Contains(item) && Region.ActiveViews.Contains(item))
            {
                Region.Deactivate(item);
            }
            else
            {
                //now check to see if we have any views that were injected
                var contentControl = item as ContentControl;
                if (contentControl != null)
                {
                    var injectedView = contentControl.Content;
                    if (Region.Views.Contains(injectedView) && Region.ActiveViews.Contains(injectedView))
                        Region.Deactivate(injectedView);
                }
            }
        }

        if (e.NewValue != null)
        {
            var item = e.NewValue;

            //are we dealing with a ContentPane directly
            if (Region.Views.Contains(item) && !this.Region.ActiveViews.Contains(item))
            {
                Region.Activate(item);
            }
            else
            {
                //now check to see if we have any views that were injected
                var contentControl = item as ContentControl;
                if (contentControl != null)
                {
                    var injectedView = contentControl.Content;
                    if (Region.Views.Contains(injectedView) && !this.Region.ActiveViews.Contains(injectedView))
                        Region.Activate(injectedView);
                }
            }
        }
    }

    void ActiveViews_CollectionChanged(object sender, NotifyCollectionChangedEventArgs e)
    {
        if (e.Action == NotifyCollectionChangedAction.Add)
        {
            FrameworkElement frameworkElement = e.NewItems[0] as FrameworkElement;
            if (frameworkElement != null)
            {
                ContentPane contentPane = frameworkElement as ContentPane;
                if (contentPane == null)
                    contentPane = frameworkElement.Parent as ContentPane;

                if (contentPane != null && !contentPane.IsActivePane)
                    contentPane.Activate();
            }
        }
    }
}