Update Pull Request 1170 to not use C# 6 stuff.

Update Pull Request 1170 to not use C# 6 stuff.

ExtendedWPFToolkitSolution/Src/Xceed.Wpf.AvalonDock/Controls/LayoutAnchorablePaneControl.cs

@@ -62,7 +62,10 @@ namespace Xceed.Wpf.AvalonDock.Controls
 
         protected override void OnGotKeyboardFocus(System.Windows.Input.KeyboardFocusChangedEventArgs e)
         {
-            _model.SelectedContent.IsActive = true;
+            if ((_model != null) && (_model.SelectedContent != null))
+            {
+                _model.SelectedContent.IsActive = true;
+            }
 
             base.OnGotKeyboardFocus(e);
         }

ExtendedWPFToolkitSolution/Src/Xceed.Wpf.AvalonDock/Controls/LayoutItem.cs

@@ -204,9 +204,15 @@ namespace Xceed.Wpf.AvalonDock.Controls
                     _view = new ContentPresenter();
 
                     _view.SetBinding(ContentPresenter.ContentProperty, new Binding("Content") { Source = LayoutElement });
-                    _view.SetBinding( ContentPresenter.ContentTemplateProperty, new Binding( "LayoutItemTemplate" ) { Source = LayoutElement.Root.Manager } );
-                    _view.SetBinding( ContentPresenter.ContentTemplateSelectorProperty, new Binding( "LayoutItemTemplateSelector" ) { Source = LayoutElement.Root.Manager } );
-                    LayoutElement.Root.Manager.InternalAddLogicalChild( _view );
+                    if ((LayoutElement != null) && (LayoutElement.Root != null))
+                    {
+                        _view.SetBinding(ContentPresenter.ContentTemplateProperty, new Binding("LayoutItemTemplate") { Source = LayoutElement.Root.Manager });
+                        _view.SetBinding(ContentPresenter.ContentTemplateSelectorProperty, new Binding("LayoutItemTemplateSelector") { Source = LayoutElement.Root.Manager });
+                        if (LayoutElement.Root.Manager != null)
+                        {
+                            LayoutElement.Root.Manager.InternalAddLogicalChild(_view);
+                        }
+                    }
                 }
 
                 return _view;