UI element jumps after move

So Ok, this is final solution:

    private void imagePDF_Tapped(object sender, TappedRoutedEventArgs e)
    {

        tapPosition = e.GetPosition(sender as Image);

        var x = tapPosition.X;
        var y = tapPosition.Y;

        AddMarkToPosition(++countPOI, x, y);

    }

    private void AddMarkToPosition(int id, double x, double y)
    {

        Points.Add(new PointOfInterest(countPOI, x, y));

        DrawShape(x, y);
        DisplayLabel(x, y, id.ToString());    

    }

    private void DrawShape(double x, double y)
    {
        shape = new Ellipse
        {
            Width = 30,
            Height = 30,
            Fill = new SolidColorBrush(Colors.Red),
            Stroke = new SolidColorBrush(Colors.Black),
        };

        shape.SetValue(Canvas.LeftProperty, x - 15 + imageDeltaX);
        shape.SetValue(Canvas.TopProperty, y - 15 + imageDeltaY);
        Shapes.Add(shape);
        canvasPDF.Children.Add(shape);
    }

    private void DisplayLabel(double x, double y, string s)
    {
        label = new TextBlock
        {
            Foreground = new SolidColorBrush(Colors.White),
            FontSize = 25,
            Text = s

        };

        label.SetValue(Canvas.LeftProperty, x - 8 + imageDeltaX);
        label.SetValue(Canvas.TopProperty, y - 20 + imageDeltaY);
        Labels.Add(label);
        canvasPDF.Children.Add(label);
    }

    private bool IsOutOfBorders(double x, double y)
    {
        var b = true;
        if ((x > (imagePDF.ActualWidth - 30)) || (x < 0) || (y > imagePDF.ActualHeight) || (y < 0))
        {
            b = true;
        }
        else b = false;
        return b;
    }

    private void UpdatePOI()
    {
        foreach (var p in Points)
        {
            Shapes[Points.IndexOf(p)].SetValue(Canvas.LeftProperty, p.x + imageDeltaX - 15);
            Shapes[Points.IndexOf(p)].SetValue(Canvas.TopProperty, p.y + imageDeltaY - 15);

            if (IsOutOfBorders(p.x + imageDeltaX, p.y + imageDeltaY)) Shapes[Points.IndexOf(p)].Visibility = Visibility.Collapsed;
            else Shapes[Points.IndexOf(p)].Visibility = Visibility.Visible;

            Labels[Points.IndexOf(p)].SetValue(Canvas.LeftProperty, p.x + imageDeltaX - 8);
            Labels[Points.IndexOf(p)].SetValue(Canvas.TopProperty, p.y + imageDeltaY - 20);

            if (IsOutOfBorders(p.x + imageDeltaX, p.y + imageDeltaY)) Labels[Points.IndexOf(p)].Visibility = Visibility.Collapsed;
            else Labels[Points.IndexOf(p)].Visibility = Visibility.Visible;

        }
    }

    private void imagePDF_ManipulationDelta(object sender, ManipulationDeltaRoutedEventArgs e)
    {

        this.image_Transform.TranslateX += e.Delta.Translation.X;
        this.image_Transform.TranslateY += e.Delta.Translation.Y;

        imageDeltaX = this.image_Transform.TranslateX;
        imageDeltaY = this.image_Transform.TranslateY;

        UpdatePOI();

    }