message: Unmounted scene component
diff: @@ -11,6 +11,9 @@ class SceneProxy extends React.Component<{crumb: number, app: React.ComponentCla
  var {crumb, app: App} = this.props;
  ReactDOM.render(<App crumb={crumb} />, this.sceneEl.current);
  }
  + componentWillUnmount() {
  + ReactDOM.unmountComponentAtNode(this.sceneEl.current);
  + }
  render() {
  return (
  <div ref={this.sceneEl} />
  