XPath 1.0 and 2.0 Support

Altova® XMLSpy® contains the powerful XPath Analyzer window and XPath builder, which assist you in building and verifying XPath 1.0 and XPath 2.0 expressions. In the XPath Analyzer window, you simply enter an XPath expression, and XMLSpy displays the results in real time. As you're composing an expression, correct syntax is shown in black, with incorrect entries highlighted in red. Clicking any node in the result window highlights the corresponding node in the file itself. The XPath builder allows you to highlight any node in your document and automatically copy the correct XPath to the clipboard. Both tools allow you to check your XPath expressions quickly and make changes in an intuitive way, saving hours of debugging time.

http://www.altova.com/products/xmlspy/xpath_analyzer_debugger.html