Control DataGroup width
<mx:Application xmlns:mx="http://www.adobe.com/2006/mxml" xmlns:s="library://ns.adobe.com/flex/spark"> <mx:String id="txt">this is a test.</mx:String> <mx:HSlider id="slider" minimum="100" maximum="400" value="250" /> <s:DataGroup width="{slider.value}" itemRenderer="spark.skins.spark.DefaultItemRenderer"> <s:layout> <s:TileLayout orientation="rows" /> </s:layout> <s:dataProvider> <mx:ArrayCollection source="{txt.split(' ')}" /> </s:dataProvider> </s:DataGroup> </mx:Application>