When I add a GeoJson data source to the viewer with polygons and use the “clampToGround” option, it looks great in 3D and Columbus views. But when I switch to 2D view, the polygons dissapear from view. I went to the Sandcastle Ground Clamping demo and I noticed that the same thing happens with Corridor, Polygon, Rectangle and Draw Model. It works with Point with Label and Billboard though.