Hidden tool windows don't restore to same location when using lazy loading

using System;
using System.ComponentModel;
using System.IO;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Media.Imaging;
using System.Windows.Threading;
using ActiproSoftware.Windows.Controls.Docking;
using ActiproSoftware.Windows.Controls.Docking.Serialization;

namespace ActiproSoftware.Windows.ProductSamples.DockingSamples.QuickStart.LayoutLazyLoading {

    /// <summary>
    /// Provides the main window for this sample.
    /// </summary>
    public partial class MainWindow : System.Windows.Window {

        private bool isLoadingLayout = false;
        private DockSiteLayoutSerializer layoutSerializer;

        /////////////////////////////////////////////////////////////////////////////////////////////////////
        // OBJECT
        /////////////////////////////////////////////////////////////////////////////////////////////////////

        /// <summary>
        /// Initializes an instance of the <c>MainWindow</c> class.
        /// </summary>
        public MainWindow() {
            InitializeComponent();

            // Create layout serializer
            this.layoutSerializer = new DockSiteLayoutSerializer()
            {
                SerializationBehavior = DockSiteSerializationBehavior.All,
                ToolWindowDeserializationBehavior = DockingWindowDeserializationBehavior.LazyLoad
            };

            // Load the persisted layout
            this.LoadLayout();

            // Attach to the loaded event
            this.Loaded += new RoutedEventHandler(OnLoaded);
            this.Closing += new CancelEventHandler(OnClosing);
        }

        /////////////////////////////////////////////////////////////////////////////////////////////////////
        // NON-PUBLIC PROCEDURES
        /////////////////////////////////////////////////////////////////////////////////////////////////////

        /// <summary>
        /// Creates the content for a programmatic tool window.
        /// </summary>
        /// <returns>The content for a programmatic tool window.</returns>
        private static UIElement CreateContent() {
            return new TextBox() {
                BorderThickness = new Thickness(),
                IsReadOnly = true,
                Text = "This ToolWindow was programmatically created in the code-behind."
            };
        }

        /// <summary>
        /// Loads the layout from a <see cref="TextBox"/>.
        /// </summary>
        private void LoadLayout()
        {
            string dockSiteLayout = string.Empty;

            try
            {
                string dockFileName = @"C:\Temp\Actipro.layout";
                if (File.Exists(dockFileName))
                {
                    dockSiteLayout = File.ReadAllText(dockFileName);
                    this.isLoadingLayout = true;
                    this.layoutSerializer.LoadFromString(dockSiteLayout, dockSite);
                } // End if
            } // End try
            catch (Exception e)
            {
            } // End catch
            finally
            {
                this.isLoadingLayout = false;
            }
        } // End of method

        /// <summary>
        /// Occurs when the <c>Activate.Programmatic ToolWindow 1</c> menu item is clicked.
        /// </summary>
        /// <param name="sender">The sender of the event.</param>
        /// <param name="e">A <see cref="RoutedEventArgs"/> that contains the event data.</param>
        private void OnActivateProgrammaticToolWindow1Click(object sender, RoutedEventArgs e) {
            ToolWindow toolWindow = this.dockSite.ToolWindows["programmaticToolWindow1"];
            if (toolWindow == null) {
                // Create the tool window content
                TextBox textBox = new TextBox() {
                    BorderThickness = new Thickness(),
                    IsReadOnly = true,
                    Text = "This ToolWindow was programmatically created in the code-behind."
                };

                // Create the tool window
                toolWindow = new ToolWindow(this.dockSite, "programmaticToolWindow1", "Programmatic ToolWindow 1",
                    new BitmapImage(new Uri("/Resources/Images/Properties16.png", UriKind.Relative)), textBox);

                // Change the menu item's header
                this.activeProgrammaticToolWindow1.Header = "Activate Programmatic ToolWindow 1";
            }

            toolWindow.Activate();
        }

        /// <summary>
        /// Occurs when the <c>Activate.Programmatic ToolWindow 2</c> menu item is clicked.
        /// </summary>
        /// <param name="sender">The sender of the event.</param>
        /// <param name="e">A <see cref="RoutedEventArgs"/> that contains the event data.</param>
        private void OnActivateProgrammaticToolWindow2Click(object sender, RoutedEventArgs e) {
            ToolWindow toolWindow = this.dockSite.ToolWindows["programmaticToolWindow2"];
            if (toolWindow == null) {
                // Create and register the tool window
                toolWindow = new CustomToolWindow() {
                    Name = "programmaticToolWindow2"
                };
                this.dockSite.ToolWindows.Add(toolWindow);

                // Change the menu item's header
                this.activeProgrammaticToolWindow2.Header = "Activate Programmatic ToolWindow 2";
            }

            toolWindow.Activate();
        }

        /// <summary>
        /// Occurs when the sample is closed.
        /// </summary>
        /// <param name="sender">The sender.</param>
        /// <param name="e">The <see cref="CancelEventArgs"/> instance containing the event data.</param>
        private void OnClosing(object sender, CancelEventArgs e) {
            this.SaveLayout();
        }

        /// <summary>
        /// Occurs when the <c>File.Load Layout</c> menu item is clicked.
        /// </summary>
        /// <param name="sender">The sender of the event.</param>
        /// <param name="e">A <see cref="RoutedEventArgs"/> that contains the event data.</param>
        private void OnFileLoadLayoutMenuItemClick(object sender, RoutedEventArgs e) {
            this.LoadLayout();
            MessageBox.Show("Layout loaded from static member variable.");
        }

        /// <summary>
        /// Occurs when the <c>File.Save Layout</c> menu item is clicked.
        /// </summary>
        /// <param name="sender">The sender of the event.</param>
        /// <param name="e">A <see cref="RoutedEventArgs"/> that contains the event data.</param>
        private void OnFileSaveLayoutMenuItemClick(object sender, RoutedEventArgs e) {
            this.SaveLayout();
            MessageBox.Show("Layout saved to static member variable.");
        }

        /// <summary>
        /// Occurs when the sample is loaded.
        /// </summary>
        /// <param name="sender">The sender of the event.</param>
        /// <param name="e">A <see cref="RoutedEventArgs"/> that contains the event data.</param>
        private void OnLoaded(object sender, RoutedEventArgs e) {
            // Invoke so that we can ensure everything is properly loaded before persisting the layout... even from the control's
            //   Loaded event handler, property values may not yet be properly set from the XAML load
            this.Dispatcher.BeginInvoke(DispatcherPriority.Send, (DispatcherOperationCallback)delegate(object arg) {
                // Activate the first document
                if (dockSite.Documents.Count > 0)
                    dockSite.Documents[0].Activate();
                return null;
            }, null);
        }

        /// <summary>
        /// Saves the layout to a <see cref="TextBox"/>.
        /// </summary>
        private void SaveLayout() {
            if (this.isLoadingLayout)
                return;

            string dockSiteLayout = layoutSerializer.SaveToString(dockSite);
            try
            {
                // Save the dock layout
                File.WriteAllText
                    (@"C:\Temp\Actipro.layout",
                    this.layoutSerializer.SaveToString(dockSite));
            } // End try
            catch (Exception e)
            {
            } // End catch
        }

    }
}