XHTML Compliant Designer Tags generated by the designer are well-formed and properly cased for XHTML. For example, the formatting options on the toolbar generate HTML that is XHTML compliant. In addition to XHTML designer support, Visual Studio 2005 includes tools that help you write XHTML compliant code in the source editor. While working in the source editor, you can validate your HTML source code against either the XHTML 1.0 Transitional or XHTML 1.0 Strict standards. When your code fails to validate, an explanation of the validation failure is provided. Configuring XHTML compliance settings in Visual Studio Team System.