As discussed here: http://lists.w3.org/Archives/Public/public-webapps/2012AprJun/0295.html
The spec has several legacy places where it forbids dispatching trusted events. These need to be corrected in order to align with DOM4:
3.6 - NotSupportedError, last sentence
initEvent definition -- appies to more than just events created with "createEvent"
dispatchEvent's Exception list.
Fixed in latest version.
As the opener, I approve :-)