Live preview in DocumentWindow's ToolTip

Hi,

I'm trying to have a live preview of the content of a DocumentWindow in its Tooltip. I did some tests, and here is the example I'm using:

<docking:Workspace>
<docking:TabbedMdiHost>
<docking:TabbedMdiContainer>
<docking:DocumentWindow Title="Document1.txt"
DataContext="{Binding RelativeSource={RelativeSource Self}}">
<docking:DockingWindow.ToolTip>
<Grid Width="400" Height="200">
<Rectangle>
<Rectangle.Fill>
<VisualBrush Visual="{Binding Content}"/>
</Rectangle.Fill>
</Rectangle>
</Grid>
</docking:DockingWindow.ToolTip>
<TextBox Text="Move other tool windows around the 'fixed' tool window." />
</docking:DocumentWindow>
</docking:TabbedMdiContainer>
</docking:TabbedMdiHost>
</docking:Workspace>

This sample works fine when the DocumentWindow is the active one, but otherwise, the visual content is not scaled properly. Do you have any idea how I can fix this problem ?


Regards,
Jeremy