TextBox with validation loses ErrorTemplate on tab change
TabItem should be defined as follows: <TabItem Header=”Foo”> <Border> <AdornerDecorator> <Grid> <TextBox Height=”35″ > <TextBox.Text> <Binding Path=”pan_id” UpdateSourceTrigger=”PropertyChanged”> <Binding.ValidationRules> <ps:PanIdValidation /> </Binding.ValidationRules> </Binding> </TextBox.Text> </TextBox> </Grid> </AdornerDecorator> </Border> </TabItem> The issue is, the Validation.Error cues are painted in the Adorner Layer. When you switch tabs, that layer is discarded.