I have a page with 2 a4j:regions in it. The first region has an a4j:commandButton that reRenders both of those regions. When I click that button, it appears that only the second region renders.
However, when I look in firebug, I can see 2 POSTs - 1 for each region. The first region returns the correct HTML data, but the browser does not refresh that region. The browser does refresh the 2nd region with new HTML data for the 2nd region.