Dear Maintainer,

if connecting to a network fails (e.g. signal is too weak, or wrong
credentials), the authentication dialog pops up. However, the dialog can
be closed only by clicking 'Cancel', not by hitting the Escape key. This
is very annoying e.g. for eduroam users in public transport, network
manager tries to associate with networks as the bus drives by, popping
up this window in the middle of work.