<mx:Accordion 
      id="myAccordion"
      width="100%" height="100%"
      headerStyleName="myHeaderStyle">
      
      <mx:Canvas label="My First Pane">
        <mx:Text text="Hello world!" fontSize="16"/>
      </mx:Canvas>
      <mx:Canvas label="My Second Pane">
        <mx:Text text="Hello world!" fontSize="16"/>
      </mx:Canvas>
    
    </mx:Accordion>
  </mx:Application>