XUL and DOM Events bubbling
Bug 234455 landed few days ago to trunk and now the second parameter of the DOMEvent::initEvent method does work even in XUL. Earlier events were always bubbling in XUL.
This means that if you now really want to make the event bubbling and you’re using the following initialization .initEvent("eventName", false, true), it must be changed to .initEvent("eventName", true, true).