Add support in PRISM for setting header of TabControl

IRegionHostedInTabControlAware.cs

namespace Coolblue.Wpf.Toolkit.Regions
{
    public interface IRegionHostedInTabControlAware
    {
        string Header { get; }
    }
}

RegionHostedInTabControlAwareBehavior.cs

using System.Collections;
using System.Collections.Specialized;
using System.Windows;
using System.Windows.Controls;

using Coolblue.Wpf.Toolkit.Regions.RegionBehaviours.Helpers;

using Prism.Regions;
using Prism.Regions.Behaviors;

namespace Coolblue.Wpf.Toolkit.Regions.RegionBehaviours
{
    public class RegionHostedInTabControlAwareBehavior : RegionBehavior, IHostAwareRegionBehavior
    {
        public const string BEHAVIOR_KEY = "RegionHostedInTabControlAwareBehavior";
        private readonly ViewModelFromViewExtractor _viewModelFromViewExtractor;
        private TabControl _hostTabControl;

        public RegionHostedInTabControlAwareBehavior()
        {
            _viewModelFromViewExtractor = new ViewModelFromViewExtractor();
        }

        public DependencyObject HostControl { get; set; }

        protected override void OnAttach()
        {
            _hostTabControl = HostControl as TabControl;
            if(_hostTabControl != null)
            {
                if(_hostTabControl.IsLoaded)
                    ApplyTabControlAwareToTabItems(Region.Views);
                else
                    _hostTabControl.Loaded += (s, e) => ApplyTabControlAwareToTabItems(Region.Views);
                Region.Views.CollectionChanged += RegionViewsOnCollectionChanged;
            }
        }

        private void RegionViewsOnCollectionChanged(object sender, NotifyCollectionChangedEventArgs e)
        {
            if(e.Action == NotifyCollectionChangedAction.Add)
                ApplyTabControlAwareToTabItems(e.NewItems);
        }

        private void ApplyTabControlAwareToTabItems(IEnumerable newRegionViews)
        {
            foreach(var newRegionView in newRegionViews)
            {
                var tabControlAware = newRegionView as IRegionHostedInTabControlAware;
                if(tabControlAware != null)
                    ApplyTabControlAwareToTabItem(newRegionView, tabControlAware);
                else
                {
                    tabControlAware =
                        _viewModelFromViewExtractor.TryExtract(newRegionView) as IRegionHostedInTabControlAware;
                    if(tabControlAware != null)
                        ApplyTabControlAwareToTabItem(newRegionView, tabControlAware);
                }
            }
        }

        private void ApplyTabControlAwareToTabItem(object newRegionView,
                                                   IRegionHostedInTabControlAware tabControlAware)
        {
            if(_hostTabControl.IsLoaded)
            {
                var tabItemHostingRegion = GetTabItem(newRegionView);
                tabItemHostingRegion.Header = tabControlAware.Header;
            }
        }

        private TabItem GetTabItem(object tabControlAwareRegion)
        {
            return (TabItem)_hostTabControl.ItemContainerGenerator.ContainerFromItem(tabControlAwareRegion);
        }
    }
}