The applet offers "Auto Ethernet" despite that this feature is explicitly disabled in the configuration.
A bug, or a feature?
$ nmcli connection
NAME UUID TYPE DEVICE
$ nmcli device
DEVICE TYPE STATE CONNECTION
enp2s5 ethernet disconnected --
lo loopback unmanaged --
$ grep -A3 \\[m /etc/NetworkManager/NetworkManager.conf
[main]
plugins=keyfile
no-auto-default=*
$ man 5 NetworkManager.conf
...
MAIN SECTION
...
no-auto-default
Specify devices for which NetworkManager shouldn't create default
wired connection (Auto eth0). By default, NetworkManager creates a
temporary wired connection for any Ethernet device that is managed
and doesn't have a connection configured. List a device in this
option to inhibit creating the default connection for the device.
May have the special value * to apply to all devices.
...
Example:
...
no-auto-default=*
= SW
NetworkManager-1.5.1-20161104git9e4232d
network-manager-applet-1.4.3-20161025gitefdc0aa
Attachment:
nm-applet-no-auto-default.png
Description: PNG image