[flexcoders] spark ButtonBar selectedIndex out of view

[bhaq1972]

I have a spark ButtonBar with a horizontalLayout. The width of the ButtonBar is 
small ...so the end buttons don't show.
When I set the selectedIndex to one of the end buttons...its not coming into 
view.

How can I ensure the selectedItem is in view?

thanks

<s:HGroup>
  <s:ButtonBar id="buttonbar1" width="500" requireSelection="true">
    <s:layout>
     <s:HorizontalLayout />
    </s:layout>
    <s:dataProvider>
      <s:ArrayCollection source="['Button1', 'Button2', 'Button3', 'Button4', 
'Button5', 'Button6', 'Button7', 'Button8']" />
      </s:dataProvider>
   </s:ButtonBar>
   <s:TextInput id="t1" text="7"/>
   <s:Button label="selectIndex" click="buttonbar1.selectedIndex = 
Number(t1.text)"/>
</s:HGroup>