**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

domElement = div.removeChild(firstChild);
    } else if (typeof props.is === 'string') {
      
      domElement = ownerDocument.createElement(type, {is: props.is});
    } else {
      
      
      
      domElement = ownerDocument.createElement(type);
      
      
      
      
      
      if (type === 'select' && props.multiple) {
        const node = ((domElement: any): HTMLSelectElement);
        node.multiple = true;
      }
    }
  } else {
    domElement = ownerDocument.createElementNS(namespaceURI, type);
  }
  if (__DEV__) {
    if (namespaceURI === HTML_NAMESPACE) {
      if (
        !isCustomComponentTag &&
        Object.prototype.toString.call(domElement) ===
          '[object HTMLUnknownElement]' &&
        !Object.prototype.hasOwnProperty.call(warnedUnknownTags, type)
      ) {