Some people have run into the following error when loading the app:
The component 'Microsoft.WpfPerformance.AddToolDialog' does not have a resource identified by the URI '/WpfPerf;component/addtooldialog.xaml'.
This happens when you have more than one copy of Wpfperf.exe on the system. Make sure that you only have one instance of the WpfPerf.exe file on your system. If you run into any problems please let us know by posting a comment here or on the WPF forum!