Show the percentage-based sizing behavior with absolute positioning
<?xml version="1.0"?> <mx:Application xmlns:mx="http://www.adobe.com/2006/mxml" verticalGap="25"> <mx:Canvas width="200" height="75" borderStyle="solid"> <mx:HBox x="20" y="10" width="100%" height="25" backgroundColor="#666666" /> </mx:Canvas> <mx:Canvas width="200" height="75" borderStyle="solid"> <mx:HBox left="20" top="10" width="100%" height="25" backgroundColor="#666666" /> </mx:Canvas> </mx:Application>