By default, the Validation.ErrorTemplate in WPF is just a small red border without any ToolTip. In Silverlight 4, the validation error is nicely styled out-of-the-box. Here is a comparison of a ...

I have a TextBox with a validation rule that is on a tab of a TabControl. The default ErrorTemplate correctly shows (red border around TextBox) when the validation rule fails. However if there is a...