GeoJson Strokewidth is not work with clampToGround = true

This is my code:

var viewer = new Cesium.Viewer("cesiumContainer");
Cesium.GeoJsonDataSource.clampToGround  = true
viewer.scene.globe.depthTestAgainstTerrain = true
//Example 1: Load with default styling.
Sandcastle.addDefaultToolbarButton("Default styling", function () {
        stroke: Cesium.Color.RED,
        strokeWidth: 1

Sancastle Link

Entity geometry outlines are currently unsupported on terrain. Outlines are automatically disabled with clampToGround on. There is a discussion on this in our Github repository: