Hello,

After updating to React 15.0.1, we are getting the following error:

```
Uncaught TypeError: Cannot read property 'addEventListener' of null
```

![image](https://cloud.githubusercontent.com/assets/4996164/14602577/5bb4e9f2-0571-11e6-9aa1-98de49f50d76.png)

}
      });
      expectUpdates(desiredWillUpdates, desiredDidUpdates);
      
      ReactUpdates.batchedUpdates(function() {
        for (i = components.length - 1; i >= 0; i--) {
          triggerUpdate(components[i]);
        }
      });
      expectUpdates(desiredWillUpdates, desiredDidUpdates);
    }
    testUpdates(
      [root.refs.switcher.refs.box, root.refs.switcher],
      
      ['Switcher', 'Box'],
      ['Box', 'Switcher']
    );
    testUpdates(
      [root.refs.child, root.refs.switcher.refs.box],
      
      ['Box', 'Child'],
      ['Box', 'Child']
    );
    testUpdates(
      [root.refs.child, root.refs.switcher],
      
      ['Switcher', 'Box', 'Child'],
      ['Box', 'Switcher', 'Child']
    );
  });