Bug 218923

Created attachment 414097 [details]
File to launch on iOS nothing will happen by clicking on "CLICK ME"

This issue is happening only on iOS.

First you have to create the following DOM (the file attached is doing it):

<my-custom-element onclick="alert('CUSTOM BUTTON CLICKED')">
  #shadowRoot
     <span>
       "button is:"
       <slot></slot>
     </span>
  "Some Text"
</my-custom-element>

when the dom is created you can add a listener to the shadowRoot like this:

```javascript
document.querySelector('my-custom-element')
  .shadowRoot
  .addEventListener('click', () => { alert('CLICK EVENT FIRED'); });
```

now you can press the "span" and you will see no event is fired. There is no alert at all displayed.

The issue is related to the listener we have on the shadowRoot. If we don't have it the first listener is working well.


Another strange behaviour is if you had an other listener on the "span" like this:

```javascript
document.querySelector('my-custom-element')
  .shadowRoot
  .querySelector('span')
  .addEventListener('click', () => { alert('SPAN CLICKED'); });
```

Now if you press the button the probleme is fixed the 3 handlers are well called as expected.