Disable context menu on Firefox Android

I have created my own context menu and want to disable the standard menu when someone long press on a link. The following work's on Firefox Desktop and Chromium Desktop/Android, but not on Firefox Android:

window.addEventListener('contextmenu', function (e) {
  e.preventDefault();
  e.stopPropagation();
  console.log('test');
  return false;
}, false);

On Firefox Android the context menu is displayed also with the above code present. The code however is executed.

Is this a bug?