Exception handler not being invoked
public partial class Window1 : Window
{
    public Window1()
    {
        InitializeComponent();
    }

    private void button1_Click(object sender, RoutedEventArgs e)
    {
        new Thread(() =>
            {
                Dispatcher.CurrentDispatcher.UnhandledExceptionFilter += Dispatcher_UnhandledExceptionFilter;
                doer();
            }).Start();
    }
    void Dispatcher_UnhandledExceptionFilter(
        object sender,
        DispatcherUnhandledExceptionFilterEventArgs e)
    {
        MessageBox.Show("FILTER REACHED");
    }


    private void doer()
    {
        throw new NotImplementedException();
    }
}

new Thread(() =>
            {
                Dispatcher.CurrentDispatcher.UnhandledExceptionFilter += Dispatcher_UnhandledExceptionFilter;
                 Dispatcher.Invoke(new Action(()=>doer()));
            }).Start();

new Thread(() =>
    {
       Dispatcher.CurrentDispatcher.UnhandledExceptionFilter += Dispatcher_UnhandledExceptionFilter;
       Dispatcher.CurrentDispatcher.Invoke(DispatcherPriority.Normal, new ThreadStart(delegate
       {
           doer();
       }));
    }).Start();