WPF ShowDialog returns null immediately on second call

Question

I think this is a bug in the WPF framework, without going into depths of my program and why I am doing what I am doing, I wrote a simple test application to prove my theory.

Answer 1

For anyone that has the same problem, here is how you can get around it:

public App()
{
    // Preserve and temporarily switch shutdown mode
    var oldShutdownMode = ShutdownMode;
    ShutdownMode = ShutdownMode.OnExplicitShutdown;

    var dialog = new Window();
    var result = dialog.ShowDialog();
    dialog = new Window();
    result = dialog.ShowDialog(); // This will show!

    // Reset shutdown mode to original value
    ShutdownMode = oldShutdownMode;    
}