We purge it [here](https://github.com/facebook/react/blob/b11540ccb2321aeb7259fcf0b3a38aeeea35231d/src/isomorphic/ReactDebugTool.js#L88-L89) but this code doesn’t run because of the [early exit](https://github.com/facebook/react/blob/b11540ccb2321aeb7259fcf0b3a38aeeea35231d/src/isomorphic/ReactDebugTool.js#L53-L57).

Need to fix this and add a test case to make sure we don’t regress on it.

ReactDOM.render(<span className="a" />, node);
    var spanID = ReactComponentTreeDevtool.getRootIDs()[0];
    expect(ReactComponentTreeDevtool.getUpdateCount(divID)).toEqual(0);
    expect(ReactComponentTreeDevtool.getUpdateCount(spanID)).toEqual(0);
    ReactDOM.render(<span className="b" />, node);
    expect(ReactComponentTreeDevtool.getUpdateCount(divID)).toEqual(0);
    expect(ReactComponentTreeDevtool.getUpdateCount(spanID)).toEqual(1);
    ReactDOM.render(<span className="c" />, node);
    expect(ReactComponentTreeDevtool.getUpdateCount(divID)).toEqual(0);
    expect(ReactComponentTreeDevtool.getUpdateCount(spanID)).toEqual(2);
    ReactDOM.unmountComponentAtNode(node);
    expect(ReactComponentTreeDevtool.getUpdateCount(divID)).toEqual(0);
    expect(ReactComponentTreeDevtool.getUpdateCount(spanID)).toEqual(2);
  });
  it('does not report top-level wrapper as a root', () => {
    var node = document.createElement('div');
    ReactDOM.render(<div className="a" />, node);
    expect(getRootDisplayNames()).toEqual(['div']);
    ReactDOM.render(<div className="b" />, node);
    expect(getRootDisplayNames()).toEqual(['div']);
    ReactDOM.unmountComponentAtNode(node);
    expect(getRootDisplayNames()).toEqual([]);
    ReactComponentTreeDevtool.purgeUnmountedComponents();
    expect(getRootDisplayNames()).toEqual([]);
    
    
    expect(getRegisteredDisplayNames()).toEqual([]);
  });
});