VerticalLineAnnotationViewModel is not showing any AnnotationLabel MVVM

Hello,

I’m trying to display a vertical line annotation on a chart using MVVM.

In order to make it work I’ve (All the INotifyPropertyChanged are managed via the BaseViewModel)

public class GraphSurfaceBaseViewModel : BaseViewModel
{
    /// <summary>
    /// A list of annotations
    /// </summary>
    public ObservableCollection<IAnnotationViewModel> Annotations { get; private set; }

 ...
}

I create annotation that way

Graph.Annotations.Add(new VerticalLineAnnotationViewModel()
            {
                X1 = TimeOfComment,
                ShowLabel = true,
                StrokeThickness = 2,
                XAxisId = "Xaxis",
                YAxisId = "Yaxis1",
                AnnotationLabels = new ObservableCollection<AnnotationLabel>() { new AnnotationLabel() {Text = "mon test", LabelPlacement = LabelPlacement.TopRight } }

            });

And the binding to the scichartsurface is :

<s:SciChartSurface   
...         
Annotations="{s:AnnotationsBinding Annotations}"            
</s:SciChartSurface>

I’ve double check that my x axis and y axis have the same ID as the annotation.
The problem is I want to display several annotation labels but they are not appearing. I suspect a problem via the AnnotationsBinding which is not taking the AnnotationLabels from the VerticalLineAnnotationViewModel.

What I got :

What I want (paint skill here):

For the what I want, I can draw a simple vertical bar by settings showLabel = false but I suppose that all the label I previously added to the
AnnotationLabels will not be shown, that’s why I let it.

Thank you for any help.

Renaud