I have the following code to create a new user interface thread in a .NET 3.5 application.
private void OnCreateNewWindow(object sender, RoutedEventArgs e)
{
var rect = this.RestoreBounds;
double l = rect.Left;
double wth = rect.Width;
double t = rect.Top;
double ht = rect.Height;
var progressThread = new Thread(() =>
{
progressWindow = new ProgressWindow(Visibility.Collapsed) { Height = 50, Width = 50 };
progressWindow.WindowStartupLocation = WindowStartupLocation.Manual;
progressWindow.Left = l + (wth - progressWindow.Width) / 2;
progressWindow.Top = t - 35 + (ht - progressWindow.Height) / 2;
progressWindow.Show();
progressWindow.Activate();
Dispatcher.Run();
});
progressThread.SetApartmentState(ApartmentState.STA);
progressThread.Start();
}
Crash shown here: 
This works great on 32-bit versions of Windows. The first time I run this program when I restart the PC on 64-bit Windows 7, I get a null exception if running through Visual Studio or the application crashes outside of Visual Studio.
Exceptions dry details:
System.NullReferenceException was unhandled
The stack trace is shown below:
[Managed to Native Transition]
WindowsBase.dll!MS.Win32.HwndWrapper.DestroyWindow(object args) + 0xfc bytes
WindowsBase.dll!MS.Win32.HwndWrapper.Dispose(bool disposing, bool isHwndBeingDestroyed) + 0xce bytes
WindowsBase.dll!MS.Win32.HwndWrapper.Dispose() + 0x15 bytes
PresentationCore.dll!System.Windows.Media.MediaContextNotificationWindow.DisposeNotificationWindow() + 0x22 bytes
PresentationCore.dll!System.Windows.Media.MediaContext.Dispose() + 0xba bytes
[Native to Managed Transition]
[Managed to Native Transition]
WindowsBase.dll!System.Windows.Threading.Dispatcher.ShutdownImplInSecurityContext(object state) + 0x47 bytes
mscorlib.dll!System.Threading.ExecutionContext.runTryCode(object userData) + 0x178 bytes
[Native to Managed Transition]
[Managed to Native Transition]
mscorlib.dll!System.Threading.ExecutionContext.Run(System.Threading.ExecutionContext executionContext, System.Threading.ContextCallback callback, object state) + 0x62 bytes
WindowsBase.dll!System.Windows.Threading.Dispatcher.ShutdownImpl() + 0x87 bytes
WindowsBase.dll!System.Windows.Threading.Dispatcher.PushFrameImpl(System.Windows.Threading.DispatcherFrame frame) + 0x121 bytes
> EMS.Controls.Dictionary.dll!EMS.Controls.Dictionary.Views.AuthenticateWindow.OnCreateNewWindow.AnonymousMethod() Line 56 + 0x5 bytes C#
mscorlib.dll!System.Threading.ExecutionContext.Run(System.Threading.ExecutionContext executionContext, System.Threading.ContextCallback callback, object state) + 0x9b bytes
mscorlib.dll!System.Threading.ThreadHelper.ThreadStart() + 0x4d bytes
If I run the program again, I get a message from the program compatibility assistant, indicating that some compatibility settings have been applied. The next time I run the program, I no longer get this exception. Has anyone experienced this?
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