当控件可见时，WPF IDATAError不显示

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 the record. Does anyone know how I can refresh the UI or get the error template to show? Thanks!I have a weird issue with the ErrorTemplate. I