Multiple VPN connections are incorrectly handled by the NetworkManager applet

 * Cinnamon version (cinnamon --version) - 3.6.6
 * Distribution - Fedora 27
 * Graphics hardware *and* driver used - Not relevant
 * 64 bit

Issue
Currently, NetworkManager supports concurrent VPN connections, which the current design of the applet doesn't account for. When I connect to a second VPN, there is no visual indication in the applet of this connection and the on/off slider does not turn off this connection. The only way to see if the connection is active and disconnect, is to go into the network settings dialogue, which displays the correct status for each VPN connection.

Steps to reproduce
Connect to two VPNs simultaneously.

Expected behaviour
Have a correct display of the connection status in the NetworkManager applet list, VPN on/off slider should start (or terminate) all VPN connections, clicking on an already connected VPN in the NetworkManager applet list should disconnect that VPN.

Start by reproducing the issue in the NetworkManager applet with two simultaneous VPN connections, then trace how the applet list and VPN on/off slider determine connection status. Done means both VPNs are visibly represented, the slider controls all VPN connections, and clicking an active VPN disconnects only that VPN.