Change to Easeljs/events/EventDispatcher.js to support multiple space-separated event types.

EventDispatcher.js

var EventDispatcher = function() {
  this.initialize();
};

var p = EventDispatcher.prototype;

EventDispatcher.initialize = function(target) {
    target.addEventListener = p.addEventListener;
    target.removeEventListener = p.removeEventListener;
    target.removeAllEventListeners = p.removeAllEventListeners;
    target.hasEventListener = p.hasEventListener;
    target.dispatchEvent = p.dispatchEvent;
};

p._listeners = null;
p.initialize = function() {};

p.addEventListener = function(types, listener) {
    var type, i = 0, typesArr = types.split(" "), listeners = this._listeners;
    if (!listeners) { listeners = this._listeners = {}; }
    else { this.removeEventListener(types, listener); }
    while (type = typesArr[i++]) {
        var arr = listeners[type];
        if (!arr) { arr = listeners[type] = []; }
        arr.push(listener);
    }
    return listener;
};

p.removeEventListener = function(types, listener) {
    types = types.split(" ");
    var type, i = 0, listeners = this._listeners;
    if (!listeners) { return; }
    while (type = types[i++]) {
        var arr = listeners[type];
        if (!arr) { return; }
        for (var i=0,l=arr.length; i<l; i++) {
            if (arr[i] == listener) {
                if (l==1) { delete(listeners[type]); } // allows for faster checks.
                else { arr.splice(i,1); }
                break;
            }
        }
    }    
};

p.removeAllEventListeners = function(types) {
    var type, i = 0;
    if (!types) { this._listeners = null; }
    else if (this._listeners) {
        types = types.split(" ");
        while (type = types[i++]) { delete(this._listeners[type]); }
    }
};

p.dispatchEvent = function(eventObj, target) {
    var ret=false, listeners = this._listeners;
    if (eventObj && listeners) {
        if (typeof eventObj == "string") { eventObj = {type:eventObj}; }
        var arr = listeners[eventObj.type];
        if (!arr) { return ret; }
        eventObj.target = target||this;
        arr = arr.slice(); // to avoid issues with items being removed or added during the dispatch
        for (var i=0,l=arr.length; i<l; i++) {
            var o = arr[i];
            if (o.handleEvent) { ret = ret||o.handleEvent(eventObj); }
            else { ret = ret||o(eventObj); }
        }
    }
    return !!ret;
};

p.hasEventListener = function(type) {
    var listeners = this._listeners;
    return !!(listeners && listeners[type]);
};


p.toString = function() {
    return "[EventDispatcher]";
};