message: fix handling groups with null colorBy
diff: @@ -73,7 +73,7 @@ export default class FilteringManager {
  for ( let child of clone.children ) {
  this.setMaterial( child, material )
  }
  - } else if ( clone.material !== undefined ) {
  + } else if ( clone.material !== undefined && material !== undefined ) {
  clone.material = material
  clone.material.clippingPlanes = this.viewer.sectionBox.planes
  }
  