New Post: AvalonDock TextBox with validation loses error template when tab changed

Hi, I am using AvalonDock and have come across a problem when using validation on user input, specifically TextBox. The validation works OK and displays the red border and tooltip when there is an error until the user switches to a different tab and then back again - the red border is lost (the tooltip error does remain). I have read that this is because the red border is painted in the AdornerLayer which is discarded when the tab is switched. Some articles suggest fixes by changing the TabItem template to include the following:

<Border>
  <AdornerDecorator>
    <StackPanel>
    ...
   </StackPanel>
  </AdornerDecorator>
</Border>

... but how can I do this with AvalonDock?