*feature*

>Warning: A component is `contentEditable` and contains `children` managed by React. It is now your responsibility to guarantee that none of those nodes are unexpectedly modified or duplicated. This is probably not intentional.

It would help heaps if I would know _which_ component is causing this.
var stubStyle = container.firstChild.style;
      styles = {display: 'block'};
      ReactDOM.render(<div style={styles} />, container);
      expect(stubStyle.display).toEqual('block');
    });
    it('should update styles if updated to null multiple times', () => {
      var styles = null;
      var container = document.createElement('div');
      ReactDOM.render(<div style={styles} />, container);
      styles = {display: 'block'};
      var stubStyle = container.firstChild.style;
      ReactDOM.render(<div style={styles} />, container);
      expect(stubStyle.display).toEqual('block');
      ReactDOM.render(<div style={null} />, container);
      expect(stubStyle.display).toEqual('');
      ReactDOM.render(<div style={styles} />, container);
      expect(stubStyle.display).toEqual('block');
      ReactDOM.render(<div style={null} />, container);
      expect(stubStyle.display).toEqual('');
    });
    it('should allow named slot projection on both web components and regular DOM elements', () => {
      var container = document.createElement('div');
      ReactDOM.render(
        <my-component>
          <my-second-component slot="first" />
          <button slot="second">Hello</button>
        </my-component>,
        container,
      );
      var lightDOM = container.firstChild.childNodes;