Exceptions are thrown when using SimpleViewer and Visual Studio 2010 for optional elements that are not set within your sample XML Document.
Although the Exceptions are handled within the SimpleViewer, Visual Studio 2010 still stops at the point the Exception is Raised.
To work around this issue, you can either press F5 to ignore each exception as is it raised, or you can turn off breaking on User-unhandled 'Common Language Runtime Exceptions' in the Debug->Exceptions Dialog (Ctrl+Alt+E).
This issue does not occur in Visual Studio 2003, 2005 or 2008.
Note: The code in the SampleApp will have already called FromXmlFile(...) to read in your XML document before the SimpleViewer is launched. If the incoming XML is invalid, an Exception will have been raised by FromXmlFile(...) and displayed in a message box.