I usually write something like this:
<mx:VBox height="100%" width="155">
<mx:Button label="b1" width="100%"/>
<mx:Buttonlabel="b2" width="100%"/>
<mx:Button label="b3" width="100%"/>
<mx:Button label="b4" width="100%"/>
</mx:VBox>
So I need all the child components to be 100%, anybody knows any other way of doing this, like without having to specify 100% for all children.