MediaElement not always playing video in WPF application

Question

we created a test application were users interact with it using gestures. Each user gets to interact with all gestures in a sequential manner. When the users first is introduced to a new gesture, a small instructional movie is played for the user showing him how to perform that gesture. The movie should first play on the main screen, and then after playing once should loop on the second monitor until the next gesture starts, when it should then close the secondary video screen and start the process over. This is where we are running into problems.

The movies all get loaded up fine, and actually most of the time play correctly. The problem is that sometimes, the movie does not actually start in the secondary monitor. They load up fine but never actually start. This is not something we can reliably reproduce, this happens sometimes at random.

This is the code that we have for the VideoPlayer window at the moment:

public partial class VideoWindow : Window {

    static VideoWindow currentVideoWindow;

    public VideoWindow(GestureDirection direction, GestureType type, bool reopen = false)
    {
        if(currentVideoWindow != null) {
            currentVideoWindow.CloseWindow();
            currentVideoWindow = this;
        }
        else {
            currentVideoWindow = this;
        }
        GestureParser.Pause(!reopen);
        InitializeComponent();
        this.Title = type + " " + direction;
        this.Show();

        videoMediaElement.LoadedBehavior = MediaState.Manual;
        videoMediaElement.UnloadedBehavior = MediaState.Manual;
        string videoDirectory = @"techniques/";
        string video = direction.ToString() + "_" + type.ToString() + ".mp4";


        if (Screen.AllScreens.Length > 1) {
            int secScreen = Screen.AllScreens.Length == 2 ? 0 : 2;
            int mainScreen = Screen.AllScreens.Length == 2 ? 1 : 0;
            Screen s = reopen ? Screen.AllScreens[secScreen] : Screen.AllScreens[mainScreen];
            System.Drawing.Rectangle r = s.WorkingArea;
            this.Top = r.Top;
            this.Left = r.Left;
            this.Topmost = true;
            this.Show();
            this.WindowStyle = WindowStyle.None;
            this.WindowState = WindowState.Maximized;
        }
        else {
            Screen s = Screen.AllScreens[0];
            System.Drawing.Rectangle r = s.WorkingArea;
            this.Top = r.Top;
            this.Left = r.Left;
            this.Show();
        }
        String videoPath = CreateAbsolutePathTo(videoDirectory + video);
        if (File.Exists(videoPath)) {
            Uri videoUri = new Uri(videoPath, UriKind.Relative);
            videoMediaElement.Source = videoUri;
        }


        if (reopen) {
            this.Activate();
            canvasWindow.Activate();
            videoMediaElement.MediaEnded += (sender, args) => {
                videoMediaElement.Stop();
                videoMediaElement.Position = TimeSpan.Zero;
            };
        } else {
            videoMediaElement.MediaEnded += (sender, args) => {
                this.CloseWindow();
                var t = new VideoWindow(direction, type, true);
            };
        }
        videoMediaElement.Play();

        Task task = Task.Factory.StartNew(() =>
        {
            while(GetMediaState(videoMediaElement) != MediaState.Play)
            {
                videoMediaElement.Play();
            }
        });
    }

    private MediaState GetMediaState(MediaElement myMedia)
    {
        FieldInfo hlp = typeof(MediaElement).GetField("_helper", BindingFlags.NonPublic | BindingFlags.Instance);
        object helperObject = hlp.GetValue(myMedia);
        FieldInfo stateField = helperObject.GetType().GetField("_currentState", BindingFlags.NonPublic | BindingFlags.Instance);
        MediaState state = (MediaState)stateField.GetValue(helperObject);
        return state;
    }

    static CanvasWindow canvasWindow;
    public static void SetCanvasWindow(CanvasWindow window) {
        canvasWindow = window;
    }

    private static string CreateAbsolutePathTo(string mediaFile) {
        return Path.Combine(new FileInfo(Assembly.GetExecutingAssembly().Location).DirectoryName, mediaFile);
    }

    private void CloseWindow() {
        videoMediaElement.Stop();
        videoMediaElement.Close();
        this.Close();
    }

}

As you can see, we have tried creating a task that constantly checks to see if the video is playing, and if not it should play it. The thing is, the media state is always playing, even if the movie is stopped, and as such it does nothing.

We really don't know what is wrong, and would really appreciate some help.