I sell a WPF application, on one customer machine (out of several hundreds) the entire application window is black, anyone know what's going on?

The machine is running Windows XP with .net 3.5SP1, the graphic adapter is GeForce 6200 with two monitors (disabling one monitor doesn't solve the problem).

Setting "Compatibility settings" to "256 colors" solves the problem (but it's not a viable solution, I need more colors for the app to look good).

The application is yaTimer ( <http://www.nbdtech.com/yaTimer/> ), it has custom window chrome based on the techniques described in this post <http://blogs.msdn.com/wpfsdk/archive/2008/09/08/custom-window-chrome-in-wpf.aspx> in the "Office 2007 without Aero" section.

If anyone can give me a clue as to what's going on I'll be very thankful.

Thanks.