With systray enabled for Networkmanager in KDE Sytem Settings plasma desktop hangs a minute after startup. 
After this long time to log into plasma 5: plasma-nm ends up with a unclickable blank icon. 
Same effekt starting kde5-nm-connection-editor via systray-icon or directly via console. 
Disabling network in systray stops the login-problem, but not the plasma-nm problems.

The functionality of kde5-nm-connection-editor seems to be broken too:
Change or add Wifi-connections.

plasma-nm or kde5-nm-connection-editor seems no longer can connect to networkmanager-qt.

Output after starting kde5-nm-connection-editor in 15.10 it look like that: 
... 
networkmanager-qt: void NetworkManager::NetworkManagerPrivate::propertiesChanged(const QVariantMap&) Unhandled property "Devices" 
...

Output after starting kde5-nm-connection-editor in 15.04 it look like that: 
...
networkmanager-qt: Connections list networkmanager-qt: "/org/freedesktop/NetworkManager/Settings/0" 
networkmanager-qt: "/org/freedesktop/NetworkManager/Settings/1" 
networkmanager-qt: "/org/freedesktop/NetworkManager/Settings/2" 
networkmanager-qt: "/org/freedesktop/NetworkManager/Settings/3" 
networkmanager-qt: "/org/freedesktop/NetworkManager/Settings/4" 
networkmanager-qt: "/org/freedesktop/NetworkManager/Settings/5" 
networkmanager-qt: "/org/freedesktop/NetworkManager/Settings/6" 
networkmanager-qt: "/org/freedesktop/NetworkManager/Settings/7" 
networkmanager-qt: "/org/freedesktop/NetworkManager/Settings/8" 
networkmanager-qt: "/org/freedesktop/NetworkManager/Settings/9" 
networkmanager-qt: Connections list networkmanager-qt: Device list 
networkmanager-qt: "/org/freedesktop/NetworkManager/Devices/0" 
networkmanager-qt: "/org/freedesktop/NetworkManager/Devices/1" 
networkmanager-qt: "/org/freedesktop/NetworkManager/Devices/2" 
networkmanager-qt: "/org/freedesktop/NetworkManager/Devices/3" 
networkmanager-qt: "/org/freedesktop/NetworkManager/Devices/4" 
networkmanager-qt: "/org/freedesktop/NetworkManager/Devices/5"
...
modemmanager-qt: Adding device "/org/freedesktop/ModemManager1/Modem/0" modemmanager-qt: "/org/freedesktop/ModemManager1/Modem/0" has interfaces: (0, 1, 2, 5, 6, 10)
...
...

Reproducible: Always

Steps to Reproduce:
1. right-click on plasma-nm applet and choose "Configure Network Connections" 
2. disable and then enable "network" in system tray again. 
3. start kde5-nm-connection-editor directly via console



This bug is related to bug 354249.