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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
container: Container,
  isConcurrent: boolean,
  hydrate: boolean,
) {
  const root = DOMRenderer.createContainer(container, isConcurrent, hydrate);
  this._internalRoot = root;
}
ReactRoot.prototype.render = function(
  children: ReactNodeList,
  callback: ?() => mixed,
): Work {
  const root = this._internalRoot;
  const work = new ReactWork();
  callback = callback === undefined ? null : callback;
  if (__DEV__) {
    warnOnInvalidCallback(callback, 'render');
  }
  if (callback !== null) {
    work.then(callback);
  }
  DOMRenderer.updateContainer(children, root, null, work._onCommit);
  return work;
};
ReactRoot.prototype.unmount = function(callback: ?() => mixed): Work {
  const root = this._internalRoot;
  const work = new ReactWork();
  callback = callback === undefined ? null : callback;
  if (__DEV__) {
    warnOnInvalidCallback(callback, 'render');
  }