How do you update the root view title in Flex

Question

Is there a way to update at runtime the root view title in Flex?

I tried something along the lines of:

<s:View xmlns:fx="http://ns.adobe.com/mxml/2009" xmlns:s="library://ns.adobe.com/flex/spark" title="{title}" activate="populateTitle()">

with

function populateTitle () { title = "updated!"; }

... but the title isn't updating!