According to the docs, EventDispatcher::dispatchEvent() should return false if either something during dispatch goes wrong or if the method preventDefault() of the Event-object was called.
But in html5 it returns true, albeit preventDefault() was called.
Have tested it with openfl 8.0.2 + lime 6.3.0 and also with openfl 8.2.2 and lime 6.4.0
Here a small test:
function test()
{
var dispatcher:IEventDispatcher = new EventDispatcher();
dispatcher.addEventListener("test123", handleEvent);
var evt:Event = new Event("test123", false, true);
var success:Bool = dispatcher.dispatchEvent(evt);
trace("evt.prev: " + evt.isDefaultPrevented()); // expected: true; got also true in html5
trace("success: " + success); // expected: false; but got true in html5
}
function handleEvent(e:Event):Void
{
e.preventDefault();
}