My GWT app works fine in DevMode if I am connected to the network. If I disconnect (turn Airport off), my app stops working. The problem occurs when the app makes an XHR request.
Googling around suggests that this is related to a Same-Origin Policy violation; but I can't understand why that would occur when I'm disconnected, and not when I'm connected.
As far as I know, all activity is localhost:8888, and localhost:9997 (for the GWT code server). I'm running DevMode using -noserver.
Any ideas?