因为在4.0中Resize 是用的<s:Resize  到4.5后又用回到<mx:Resize所以在WidgetTemplateSkin.mxml中

  <s:Resize heightTo="30"
                          target="{hostComponent}"
                          widthTo="100"/>

改为

 <mx:Resize heightTo="30"
                          target="{hostComponent}"
                          widthTo="100"/>