I created Copy of a template for TextBox using Blend. I need to edit Path.Data inside ValidationErrorElement. How do I do that? I can see XAML but I can't figure out how to edit this path data using designer.
In order to see the path in the designer (ArtBoard) you have to enable the proper Validation State.
First, select the path in the Objects and Timeline pane. Then click the States tab. Choose the ValidationStates/InvalidUnfocused or ValidationStates/InvalidFocused state.
Now you should see the path selected in the Artboard.