I use `ReactDOM.unstable_renderSubtreeIntoContainer` to render a portal.

``` javascript
class Modal extends React.Component {

componentDidMount() {
    this.node = document.createElement('div');
    document.body.appendChild(this.node);
    this.renderPortal(this.props);
}

componentWillReceiveProps(nextProps) {
    this.renderPortal(nextProps);
}

componentWillUnmount() {
    ReactDOM.unmountComponentAtNode(this.node);
    document.body.removeChild(this.node);
}

renderPortal = (props) => {
    renderSubtreeIntoContainer(this, <ModalPortal {...props} />, this.node);
}

render() {
    return null;
  }
}
```

In my root component:

``` javascript
class App extends React.Component {
    static childContextTypes = {
        highlightColor: React.PropTypes.object
    }

    getChildContext() {
        return {
            highlightColor: this.props.highlightColor
        }
    }

    ...
}
```

The context of root component will be updated and passed to children if  `this.props.highlightColor` is changed. This is right.
I can access the correct context in the `<ModalPortal/>` component in the first render.
And after that the context passed to  `<ModalPortal/>` **does not change any more** when the context of root component changed.
But I can access the correct context in the `<Modal/>`  every render.

what's wrong with my code ?

if (callback) {
        ReactUpdateQueue.enqueueCallbackInternal(prevComponent, callback);
      }
    });
    return prevComponent;
  },
  /**
   * Render a new component into the DOM. Hooked by devtools!
   *
   * @param {ReactElement} nextElement element to render
   * @param {DOMElement} container container to render into
   * @param {boolean} shouldReuseMarkup if we should skip the markup insertion
   * @return {ReactComponent} nextComponent
   */
  _renderNewRootComponent: function(
    nextElement,
    container,
    shouldReuseMarkup,
    context
  ) {
    if (__DEV__) {
      ReactInstrumentation.debugTool.onBeginFlush();
    }
    
    
    
    warning(
      ReactCurrentOwner.current == null,
      '_renderNewRootComponent(): Render methods should be a pure function ' +
      'of props and state; triggering nested component updates from ' +