New to AS3, does this class look correct?

I hope this isn’t faux pas, but I’m making the transition from AS2 to AS3 and was wondering if I’m on the right track with this class. One question in particular I have is, I’m storing a reference (I think it’s just a reference and not a copy) of “curTab” in order to keep track of the currently selected tab in this UI navigation. Is this using unnecessary memory and is there a better way to do this?

package cardmaker {
    import flash.display.*;
    import flash.events.*;
    
    public class Navigation extends MovieClip {
        
        private var navRoot:MovieClip = StaticVars.MovieRoot.nav_mc;
        private var curTab:Object;
        
        public function Navigation():void {
            var i:int = navRoot.numChildren;trace(i);
            while (i--){
                var btn:Object = navRoot.getChildAt(i);
                
                btn.addEventListener(MouseEvent.MOUSE_OVER, onNavBtnMouseOver);
                btn.addEventListener(MouseEvent.MOUSE_OUT, onNavBtnMouseOut);
                btn.addEventListener(MouseEvent.CLICK, onNavBtnClick);
                
                // Focus first tab
                if(i==0)
                    focus_tab(btn);
            }
        }
        
        private function onNavBtnMouseOver(evt:MouseEvent){
            evt.target.buttonMode = true;
            evt.target.gotoAndStop('on');
        }
        private function onNavBtnMouseOut(evt:MouseEvent){
            if(curTab != evt.target)
                evt.target.gotoAndStop('off');
        }
        private function onNavBtnClick(evt:MouseEvent){
            blur_tabs();
            focus_tab(evt.target);
        }
        public function focus_tab(tab:Object):void {
            curTab = tab;
            MovieClip(tab).gotoAndStop("on");
        }
        public function blur_tabs():void {
            var i:int = navRoot.numChildren;trace(i);
            while (i--){
                MovieClip(navRoot.getChildAt(i)).gotoAndStop("off");
            }
        }
    }
}