Enable child of TabNavigator
<mx:Application xmlns:mx="http://www.adobe.com/2006/mxml" layout="absolute"> <mx:Canvas width="400" height="300"> <mx:Script> import mx.core.UIComponent; public function disableTab(value:int = 0):void{ if(value == 0){ (navigator.getChildAt(navigator.numChildren - 1) as UIComponent).enabled = false; } else { (navigator.getChildAt(value) as UIComponent).enabled = false; } } </mx:Script> <mx:TabNavigator id="navigator"> </mx:TabNavigator> </mx:Canvas> </mx:Application>