It seems that by default network-admin does not write "auto wlan0" in /etc/network/interfaces.
This can be fixed by editing ~/.gnome2/network-admin-locations/<name of location> and changing auto=false to auto=true in the section corresponding to the wireless interface. I'm not sure why this is necessary, though.
I found some sort of fix for it.
It seems that by default network-admin does not write "auto wlan0" in /etc/network/ interfaces. network- admin-locations /<name of location> and changing auto=false to auto=true in the section corresponding to the wireless interface. I'm not sure why this is necessary, though.
This can be fixed by editing ~/.gnome2/