Using the constructor `new Event()` is not supported in IE >= 9.0 (tested on IE 11). It raises the below error: `Object doesn't support this action` This revision implements the Polyfill `CustomEvent()` suggested by the MDN here: https://developer.mozilla.org/en-US/docs/Web/API/CustomEvent/CustomEvent and uses it if the `new Event()` call fails. opw-690984