Commented Unassigned: AvalonDock and XamlWriter.Save: stack overflow exception [21893]

Hi all,
I tried to save my dock manager and document pane (empty, without other wpf objects) to xaml string but I had no success, I got always stack overflow exception. Why? Is there a reference in layoutdocument object to its parent? Does exist a way to got it?

Thanks in advance,
Fabio
Comments: ** Comment from web user: FabioMarcone **

Xaml:
<xcad:DockingManager x:Name="dockManager"
AllowMixedOrientation="True"
BorderBrush="Black"
BorderThickness="1"
>
<xcad:DockingManager.DocumentHeaderTemplate>
<DataTemplate>
<StackPanel Orientation="Horizontal">
<Image Source="{Binding IconSource}" Margin="0,0,4,0"/>
<TextBlock Text="{Binding Title}" />
</StackPanel>
</DataTemplate>
</xcad:DockingManager.DocumentHeaderTemplate>
<xcad:LayoutRoot x:Name="_layoutRoot">
<xcad:LayoutPanel Orientation="Horizontal">
<xcad:LayoutAnchorablePane x:Name="AnchorablePane" DockWidth="2*" DockMinWidth="250">
<!--xcad:LayoutAnchorable ContentId="properties" Title="Properties" CanHide="False" CanClose="False"
AutoHideWidth="240"
>
<xctk:PropertyGrid NameColumnWidth="110"
SelectedObject="{Binding ElementName=_layoutRoot, Path=LastFocusedDocument.Content}"/>
</xcad:LayoutAnchorable-->
<xcad:LayoutAnchorable ContentId="tools" Title="Tools" CanHide="True" CanClose="False" AutoHideWidth="240">
<StackPanel Orientation="Vertical">
<Button x:Name="btntoolsAddDockWindow" Click="btntoolsAddDockWindow_Click">ADD DOCK WINDOW</Button>
<Button x:Name="btntoolsAddLeftWindow" Click="btntoolsAddLeftWindow_Click">ADD LEFT WINDOW</Button>
<Button x:Name="btntoolsAddRightWindow" Click="btntoolsAddRightWindow_Click">ADD RIGHT WINDOW</Button>
<Button x:Name="btntoolsAddTopWindow" Click="btntoolsAddTopWindow_Click">ADD TOP WINDOW</Button>
<Button x:Name="btntoolsAddBottomWindow" Click="btntoolsAddBottomWindow_Click">ADD BOTTOM WINDOW</Button>

</StackPanel>
</xcad:LayoutAnchorable>
</xcad:LayoutAnchorablePane>
<xcad:LayoutDocumentPaneGroup DockWidth="4*">
<xcad:LayoutDocumentPane x:Name="DocumentPane">
<!-- Documents here-->

</xcad:LayoutDocumentPane>
</xcad:LayoutDocumentPaneGroup >
<xcad:LayoutAnchorablePaneGroup DockWidth="2*" DockMinWidth="250">
<xcad:LayoutAnchorablePane>
<xcad:LayoutAnchorable ContentId="plugins" Title="{DynamicResource Localization_Plugins}" >
<StackPanel Orientation="Vertical" Name="spConfiguredPlugins">

</StackPanel>
</xcad:LayoutAnchorable>
<xcad:LayoutAnchorable ContentId="guiobjects" Title="{DynamicResource Localization_GuiObjects}" >
<StackPanel Orientation="Vertical" Name="spAvailableGuiObjects">

</StackPanel>
</xcad:LayoutAnchorable>
</xcad:LayoutAnchorablePane>
</xcad:LayoutAnchorablePaneGroup>
</xcad:LayoutPanel>

<xcad:LayoutRoot.LeftSide>
<xcad:LayoutAnchorSide>
<xcad:LayoutAnchorGroup x:Name="AnchorGroupLeft">

</xcad:LayoutAnchorGroup>
</xcad:LayoutAnchorSide>
</xcad:LayoutRoot.LeftSide>
<xcad:LayoutRoot.RightSide>
<xcad:LayoutAnchorSide>
<xcad:LayoutAnchorGroup x:Name="AnchorGroupRight">

</xcad:LayoutAnchorGroup>
</xcad:LayoutAnchorSide>
</xcad:LayoutRoot.RightSide>
<xcad:LayoutRoot.TopSide>
<xcad:LayoutAnchorSide>
<xcad:LayoutAnchorGroup x:Name="AnchorGroupTop">

</xcad:LayoutAnchorGroup>
</xcad:LayoutAnchorSide>
</xcad:LayoutRoot.TopSide>
<xcad:LayoutRoot.BottomSide>
<xcad:LayoutAnchorSide>
<xcad:LayoutAnchorGroup x:Name="AnchorGroupBottom">

</xcad:LayoutAnchorGroup>
</xcad:LayoutAnchorSide>
</xcad:LayoutRoot.BottomSide>
</xcad:LayoutRoot>
</xcad:DockingManager>

in code behind XamlWriter.Save(dockManager.DocumentPane) raises StackOverflow exception.

Thanks.