Seems there's a lot of old problems resurfacing today.
As I went to test the navigation in my nifty new Messenger portlet I found the buttons doing absolutely nothing. I was using static JSF navigation... Nothing. I tried a test action method and a test button... nothing.
Well it seems Chrome and Firefox can't handle it either these days, at least not in a Liferay 6 environment.
Add this to your web.xml:
And all will be well.