Apologies if this is an FAQ or if it has already been fixed but I drew a blank searching for Jessie and Wifi config.
I have just downloaded the full version of Nov 2015 version of Raspbian Jessie from https://downloads.raspberrypi.org/raspbian_latest and have installed in my Raspi Zero board.
I was somewhat surprised to find that the Wifi Config icon is missing from the Desktop and this function is not in any of the menus. I am sure I had read that the new Desktop interface had this feature.
iwconfig scan shows that several access points are available so I am sure I will crack this on the command line.
However, I am concerned that this omission, if that is what it is, is picked up in the next update. Of course, until I get wifi working I cant fetch any updates which is a bit of a catch 22.