Merge pull request #1188 from xceedsoftware/revert-1187-pr/451

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

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

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

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

@@ -72,8 +72,6 @@ namespace Xceed.Wpf.AvalonDock.Controls
 
             _model.ChildrenTreeChanged += (s, args) =>
                 {
-                    if (args.Change != ChildrenTreeChange.DirectChildrenChanged)
-                        return;
                     if (_asyncRefreshCalled.HasValue &&
                         _asyncRefreshCalled.Value == args.Change)
                         return;

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

@@ -204,15 +204,9 @@ namespace Xceed.Wpf.AvalonDock.Controls
                     _view = new ContentPresenter();
 
                     _view.SetBinding(ContentPresenter.ContentProperty, new Binding("Content") { Source = LayoutElement });
-                    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);
-                        }
-                    }
+                    _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);
                 }
 
                 return _view;