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 ?

var checksum = rootElement.getAttribute(
          ReactMarkupChecksum.CHECKSUM_ATTR_NAME
        );
        rootElement.removeAttribute(ReactMarkupChecksum.CHECKSUM_ATTR_NAME);
        var rootMarkup = rootElement.outerHTML;
        rootElement.setAttribute(
          ReactMarkupChecksum.CHECKSUM_ATTR_NAME,
          checksum
        );
        var normalizedMarkup = markup;
        if (__DEV__) {
          
          
          
          
          var normalizer;
          if (container.nodeType === ELEMENT_NODE_TYPE) {
            normalizer = document.createElement('div');
            normalizer.innerHTML = markup;
            normalizedMarkup = normalizer.innerHTML;
          } else {
            normalizer = document.createElement('iframe');
            document.body.appendChild(normalizer);
            normalizer.contentDocument.write(markup);
            normalizedMarkup = normalizer.contentDocument.documentElement.outerHTML;
            document.body.removeChild(normalizer);
          }
        }
        var diffIndex = firstDifferenceIndex(normalizedMarkup, rootMarkup);
        var difference = ' (client) ' +