How to clip a polygon to the ground et stay fixed ?

Hi guys !
i'm needing some help, i'm using Césium at Work, i was able to create Polygon, save it to my database, but all of my polygons are not set on the ground.

I tried this :

Cesium.GeoJsonDataSource.load(result.object, {
                                stroke: Cesium.Color.HOTPINK,
                                fill: Cesium.Color.PINK,
                                strokeWidth: 3,
                                markerSymbol: '?',
                                clampToGround : true <----------

It's not working already, when i'm scrolling view or just swip, my polygon is mooving around him self. This moove from the polygon is not too much but i really need to clip him on the ground.
I got some screens already if needed !
If someone already go through this, thank's by advance !



Have you tried adding this line:

Cesium.GeoJsonDataSource.clampToGround = true;