Loaded SWF Background dissappears on load!

programming flash
1

I’m loading a SWF into my movie – using code below. The only thing is that if I have a SWF that has a colored background, and content above that, on loading the background of the imported SWF comes through as transparent (i.e. the color doesn’t show) and only the objects in the imported SWF show up –

Why would this be? How to fix? (I can add a colored rectangle that takes up whole stage – that works OK, but wonder why actual background doesn’t show)

Thanks!

public function loadContent(url:String):void {
            var request:URLRequest = new URLRequest(url);
            var loader:Loader = new Loader();

            loader.contentLoaderInfo.addEventListener(Progress  Event.PROGRESS, loadProgress);
            loader.contentLoaderInfo.addEventListener(Event.CO  MPLETE, loadComplete);
            loader.load(request);
            addChild(loader);
        }
        function loadProgress(event:ProgressEvent):void {
            var percentLoaded:Number = event.bytesLoaded/event.bytesTotal;
            percentLoaded = Math.round(percentLoaded * 100);
            trace("Loading: "+percentLoaded+"%");
        }       function loadComplete(event:Event):void {
            trace("Complete");
        }