React context passed but not updated after setState - reactjs

Question

I manage to pass context through children but only once. Context is never updated.
Yet I have seen many examples working like that, including react docs: https://facebook.github.io/react/docs/context.html
Here is my code:
Parent Component:
class App extends React.Component {
constructor(props) {
super(props);
this.state = {
window:{
height:null,
width:null
}
};
}
getChildContext() {
return {
window: this.state.window
}
}
componentDidMount () {
window.addEventListener('resize', this.handleResize.bind(this));
this.handleResize();
}
componentWillUnmount () {
window.removeEventListener('resize', this.handleResize.bind(this));
}
handleResize (){
this.setState({
window:{
width:window.innerWidth
|| document.documentElement.clientWidth
|| document.body.clientWidth,
height:window.innerHeight
|| document.documentElement.clientHeight
|| document.body.clientHeight
}
});
}
render() {
console.log(this.state.window);
// --> working
return (
{this.props.children}
);
}
}
App.propTypes = {
children: React.PropTypes.node.isRequired
};
App.childContextTypes = {
window: React.PropTypes.object
}
export default App;
Child Component:
class Child extends React.Component {
constructor(props, context) {
super(props);
this.state = {};
}
render () {
console.log(this.context.window);
// --> passed on first render, but never updated
return (
...
)
}
}
Child.contextTypes = {
window: React.PropTypes.object.isRequired
};
export default Child
Am i missing something?