Rendering issue with the preview of the splitter line in floating windows

<Window x:Class="SampleToolWindowBugForActipro.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:docking="http://schemas.actiprosoftware.com/winfx/xaml/docking" 
        Title="MainWindow" Height="350" Width="525">
    
    <docking:DockSite UseHostedAutoHidePopups="False" 
                      AreDocumentWindowsDestroyedOnClose="False"
                      IsLiveSplittingEnabled="False">
            
        <docking:Workspace>
            <docking:TabbedMdiHost>
                <docking:TabbedMdiContainer>
                    <docking:DocumentWindow Title="DocumentWindow" />
                </docking:TabbedMdiContainer>
            </docking:TabbedMdiHost>
        </docking:Workspace>

        <docking:DockSite.AutoHideRightContainers>
            <docking:ToolWindowContainer>
                <docking:ToolWindow Title="ToolWindow1" />
            </docking:ToolWindowContainer>
        </docking:DockSite.AutoHideRightContainers>

        <docking:DockSite.AutoHideLeftContainers>
            <docking:ToolWindowContainer>
                <docking:ToolWindow Title="ToolWindow2" />
            </docking:ToolWindowContainer>
        </docking:DockSite.AutoHideLeftContainers>

    </docking:DockSite>
</Window>

Hello,

I have issues with the preview of the Splitter-Line when increasing/decreasing the
width or height of an floating window. (Version 2013.2 (build 0592))

1. Using the sample you can see, that the preview of the Splitter-Line is not rendered if you
increase the width of an floating window. (While you decrease the width it is rendered.)

2. When using WindowsFormsHost as the content of a floating window the preview of
the Splitter-Line is drawn behind the WindowsFormsHost. I know that WindowsFormsHost elements are always rendered on top of WPF. Do you know any workaround for this behaviour?

Thanks
Niels