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)

if (this._debugID !== 0) {
          ReactInstrumentation.debugTool.onEndLifeCycleTimer(
            this._debugID,
            'shouldComponentUpdate'
          );
        }
      }
    }
    if (__DEV__) {
      warning(
        shouldUpdate !== undefined,
        '%s.shouldComponentUpdate(): Returned undefined instead of a ' +
        'boolean value. Make sure to return true or false.',
        this.getName() || 'ReactCompositeComponent'
      );
    }
    if (shouldUpdate) {
      this._pendingForceUpdate = false;
      
      this._performComponentUpdate(
        nextParentElement,
        nextProps,
        nextState,
        nextContext,
        transaction,
        nextUnmaskedContext
      );
    } else {