GeoJSON, polygons, and ground clamping

I'm using Firefox 44 on Linux with Cesium 1.21. I load a multipolygon in GeoJson format. It displays, but the polygon doesn't follow the terrain, i.e. the polygon is flat.

Thanks,
  Tony

Nevermind. Just checked your change log and realized it was fixed in a later version. Bumped to 1.30 and everything looks good.

Thanks.