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**Do you want to request a *feature* or report a *bug*?**
*bug*

**What is the current behavior?**

Since React@16.5 seems that `root` element has `onclick` event handler with noop function.
In ios Safari/Chrome browsers html element has gray overlay when tap on it.

The current behavior is that the whole `root` is blinking when we tap on it.

The simple example to reproduce:
https://codesandbox.io/s/wyo8rlj1zk
The issue is reproducing only in fullscreen mode https://wyo8rlj1zk.codesandbox.io/
(root container is steel blue)

I suppose changes came from here:
https://github.com/facebook/react/pull/11927
https://github.com/facebook/react/pull/11927/files

and the issue can be related with:
https://github.com/mui-org/material-ui/issues/11154
https://github.com/facebook/react/issues/12717

**Which versions of React, and which browser / OS are affected by this issue? Did this work in previous versions of React?**
React 16.5
ios 11.3/12 Safari/Chrome
return <polymer-component />;
          }
        }
        const node = document.createElement('div');
        expect(() => ReactDOM.render(<ShadyComponent />, node)).toWarnDev(
          'ShadyComponent is using shady DOM. Using shady DOM with React can ' +
            'cause things to break subtly.',
        );
        mountComponent({is: 'custom-shady-div2'});
      } finally {
        document.createElement = defaultCreateElement;
      }
    });
    it('should emit a warning once for an unnamed custom component using shady DOM', () => {
      const defaultCreateElement = document.createElement.bind(document);
      try {
        document.createElement = element => {
          const container = defaultCreateElement(element);
          container.shadyRoot = {};
          return container;
        };
        expect(() => mountComponent({is: 'custom-shady-div'})).toWarnDev(
          'A component is using shady DOM. Using shady DOM with React can ' +
            'cause things to break subtly.',
        );
        
        mountComponent({is: 'custom-shady-div2'});
      } finally {
        document.createElement = defaultCreateElement;
      }