-Bug fix when restoring layout from xml. all of the "Sides" like leftside and rightside objects were being nulled out causing null reference exceptions when you tried to "unpin" a panel on one of the sides.

ExtendedWPFToolkitSolution/Src/Xceed.Wpf.AvalonDock/Layout/LayoutRoot.cs

@@ -17,12 +17,9 @@
 using System;
 using System.Collections.Generic;
 using System.Linq;
-using System.Text;
-using System.Windows;
 using System.Collections.ObjectModel;
 using System.Windows.Markup;
 using System.Xml.Serialization;
-using Standard;
 using System.Xml;
 using System.Xml.Schema;
 
@@ -690,30 +687,10 @@ namespace Xceed.Wpf.AvalonDock.Layout
                 }
             }
 
-          TopSide = ( LayoutAnchorSide )ReadElement( reader );
+            TopSide = GetLayoutAnchorSide(reader);
-          if( TopSide != null )
+            RightSide = GetLayoutAnchorSide(reader);
-          {
+            LeftSide = GetLayoutAnchorSide(reader);
-            TopSide.Children.Add( ( LayoutAnchorGroup )ReadElement( reader ) );
+            BottomSide = GetLayoutAnchorSide(reader);
-            reader.Read();
-          }
-          RightSide = ( LayoutAnchorSide )ReadElement( reader );
-          if( RightSide != null )
-          {
-            RightSide.Children.Add( ( LayoutAnchorGroup )ReadElement( reader ) );
-            reader.Read();
-          }
-          LeftSide = ( LayoutAnchorSide )ReadElement( reader );
-          if( LeftSide != null )
-          {
-            LeftSide.Children.Add( ( LayoutAnchorGroup )ReadElement( reader ) );
-            reader.Read();
-          }
-          BottomSide = ( LayoutAnchorSide )ReadElement( reader );
-          if( BottomSide != null )
-          {
-            BottomSide.Children.Add( ( LayoutAnchorGroup )ReadElement( reader ) );
-            reader.Read();
-          }
 
             FloatingWindows.Clear();
             var floatingWindows = ReadElementList(reader);
@@ -730,6 +707,18 @@ namespace Xceed.Wpf.AvalonDock.Layout
             }
         }
 
+        private LayoutAnchorSide GetLayoutAnchorSide(XmlReader reader)
+        {
+            var side = (LayoutAnchorSide)ReadElement(reader);
+            if (side != null)
+            {
+                side.Children.Add((LayoutAnchorGroup)ReadElement(reader));
+                reader.Read();
+            }
+
+            return side ?? new LayoutAnchorSide();
+        }
+
         private List<ILayoutPanelElement> ReadRootPanel(XmlReader reader)
         {
             var result = new List<ILayoutPanelElement>();