DeviceLost event happening but DeviceLostException never generated

[DaveTMG]

I have written a trivial Windows Forms test application to try out using
DirectX.Direct3D features. I am using VS 2008 with .NET 3.5 SP1.

I am trying to understand why the application is generating DeviceLost and
DeviceReset events but the DeviceLostException is never being generated when
I call the Device.Present method. I am resizing and minimizing the
application form in order to test out my event and exception handling.

When does this exception get generated?
Why does the event happen if the device is not really lost?

Thanks,
Dave