<?xml version="1.0" encoding="utf-8"?> <mx:Application xmlns:mx="http://www.adobe.com/2006/mxml" layout="vertical" verticalAlign="middle" backgroundColor="white"> <mx:Style> .myCustomButtonStyleName { cornerRadius: 16; } </mx:Style> <mx:Array id="arr"> <mx:Object label="Button" /> <mx:Object label="ButtonBar" /> <mx:Object label="CheckBox" /> <mx:Object label="ColorPicker" /> </mx:Array> <mx:ButtonBar id="buttonBar" buttonStyleName="myCustomButtonStyleName" dataProvider="{arr}" height="32" /> </mx:Application>