Using the clipContent property
<?xml version="1.0"?> <mx:Application xmlns:mx="http://www.adobe.com/2006/mxml" width="600" height="400" > <mx:HBox id="myHBox" width="150" height="150" borderStyle="solid" clipContent="false"> <mx:TextInput id="myInput" width="200" height="40"/> </mx:HBox> </mx:Application>