Annotations on a realtime LineSerie graph

Hello mates,

I'm using Oxyplot to plot a realtime Line graph (X axis is DateTimeAxis and Y axis is LineAxis) with several lines. All works well.

Now, I want to show on screen the Minimum and Maximum of each LineSerie in the graph. Firstly, I thought this would be easy to achieve with TextAnnotations, but as my X axis moves every second, my annotation simply goes away. I would like it to stay still at the same position on screen.

I've seen someone saying something about using overlay, but I also couldn't get it to work.

Is there a way I can do it without having to update its position everytime the plot refreshes?

Thanks in advance!