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

**What is the current behavior?**
In mobile Safari, DOM events originating from elements rendered through a Portal do **not** bubble (propagate) up the React component tree.

**If the current behavior is a bug, please provide the steps to reproduce....**
Please see the following JSFiddle: https://jsfiddle.net/zebulonj/wf7orwan/

In this JSFiddle, the expected behavior (seen in a desktop browser) is that clicking on the portal content (appearing as a modal, including backdrop) should toggle to the "On" or "Off" indicator rendered in the main content. However, in mobile Safari (iOS 11.1.1), the click events do not propagate.


**What is the expected behavior?**
Click events should propagate up the React component tree.

**Which versions of React, and which browser / OS are affected by this issue? Did this work in previous versions of React?**
Affected: React 16.2
iOS 11.1.1

if (__DEV__) {
    if (didWarnInvalidHydration) {
      return;
    }
    didWarnInvalidHydration = true;
    warningWithoutStack(
      false,
      'Did not expect server HTML to contain a <%s> in <%s>.',
      child.nodeName.toLowerCase(),
      parentNode.nodeName.toLowerCase(),
    );
  }
}
export function warnForDeletedHydratableText(
  parentNode: Element | Document,
  child: Text,
) {
  if (__DEV__) {
    if (didWarnInvalidHydration) {
      return;
    }
    didWarnInvalidHydration = true;
    warningWithoutStack(
      false,
      'Did not expect server HTML to contain the text node "%s" in <%s>.',
      child.nodeValue,
      parentNode.nodeName.toLowerCase(),
    );
  }
}