WPF IDATAError no showing when control becomes visible

I have a weird issue with the ErrorTemplate. I created a WPF MVVM application. I am using a ErrorTemplate and the IDataError interface to show errors. On my form I have some controls that are collapsed in a stack panel. When I show the controls the error template is not showing but the error functionality is working because the user can't save 开发者_StackOverflow中文版the record. Does anyone know how I can refresh the UI or get the error template to show? Thanks!

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do you use an adorner for your error template? if so try

<AdornerDecorator>
   <YourStackPanel/>
</AdornerDecorator>