Refreshing bookmarked web app

Hi,

My web app has a dataview on its home page. I'm successfully using a cache buster to refresh the data whenever the user returns to the home page via the tabpanel navigation (using the "painted" event).

The problem is: how do you refresh a page (i.e., reload a store) when the user leaves the application and then returns to it? The "painted" event seemed like a reasonable choice but it doesn't seem to fire on simply returning to the active app.

Thanks!