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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
node.nodeType === DOCUMENT_NODE ||
      node.nodeType === DOCUMENT_FRAGMENT_NODE ||
      (node.nodeType === COMMENT_NODE &&
        node.nodeValue === ' react-mount-point-unstable '))
  );
}
function getReactRootElementInContainer(container: any) {
  if (!container) {
    return null;
  }
  if (container.nodeType === DOCUMENT_NODE) {
    return container.documentElement;
  } else {
    return container.firstChild;
  }
}
function shouldHydrateDueToLegacyHeuristic(container) {
  const rootElement = getReactRootElementInContainer(container);
  return !!(
    rootElement &&
    rootElement.nodeType === ELEMENT_NODE &&
    rootElement.hasAttribute(ROOT_ATTRIBUTE_NAME)
  );
}
ReactGenericBatching.setBatchingImplementation(
  DOMRenderer.batchedUpdates,
  DOMRenderer.interactiveUpdates,
  DOMRenderer.flushInteractiveUpdates,
);
let warnedAboutHydrateAPI = false;