The solution: Uncomment the code which has been commented out due to an already fixed gnome bug. This fixed the issue for me. Please confirm that it does fix it for you, too.
michael@thinkpad:/etc$ git diff NetworkManager/dispatcher.d/01ifupdown diff --git a/NetworkManager/dispatcher.d/01ifupdown b/NetworkManager/dispatcher.d/01ifupdown index ebadfd1..f4de9cc 100755 --- a/NetworkManager/dispatcher.d/01ifupdown +++ b/NetworkManager/dispatcher.d/01ifupdown @@ -55,16 +55,16 @@ for i in $ADDRESS_FAMILIES; do ;; # pre-up/pre-down not implemented. See # https://bugzilla.gnome.org/show_bug.cgi?id=387832 -# pre-up) -# export MODE="start" -# export PHASE="pre-up" -# run-parts /etc/network/if-pre-up.d -# ;; -# pre-down) -# export MODE="stop" -# export PHASE="pre-down" -# run-parts /etc/network/if-down.d -# ;; + pre-up) + export MODE="start" + export PHASE="pre-up" + run-parts /etc/network/if-pre-up.d + ;; + pre-down) + export MODE="stop" + export PHASE="pre-down" + run-parts /etc/network/if-down.d + ;; hostname|dhcp4-change|dhcp6-change) # Do nothing ;; michael@thinkpad:/etc$ ** Bug watch added: GNOME Bug Tracker #387832 https://bugzilla.gnome.org/show_bug.cgi?id=387832 -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1316634 Title: Does not automatically reconnect to hidden WiFi network To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/network-manager/+bug/1316634/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs