A recent build of Chrome added a bug where cross origin checks (such as are required to communicate with Wax LRS) do not work during the window unload event (such as when someone closes a browser window or tab). The bug has been fixed in an even more recent build, so please upgrade Chrome or temporarily switch browsers. For more information, see ´╗┐https://code.google.com/p/chromium/issues/detail?id=321241