**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

return;
    }
    didWarnInvalidHydration = true;
    const names = [];
    attributeNames.forEach(function(name) {
      names.push(name);
    });
    warningWithoutStack(false, 'Extra attributes from the server: %s', names);
  };
  warnForInvalidEventListener = function(registrationName, listener) {
    if (listener === false) {
      warning(
        false,
        'Expected `%s` listener to be a function, instead got `false`.\n\n' +
          'If you used to conditionally omit it with %s={condition && value}, ' +
          'pass %s={condition ? value : undefined} instead.',
        registrationName,
        registrationName,
        registrationName,
      );
    } else {
      warning(
        false,
        'Expected `%s` listener to be a function, instead got a value of `%s` type.',