Comment 5 for bug 1636282

After performing some more tests:

The triggers for the network-manager showing the arrow icon and no WiFi networks are:
- Suspend mode (suspend/wake up)
- Hardware wireless button (turn WiFi off/an)
- Wireless network in network-manager GUI (deactivate/activate)
- Network in network-manager GUI (deactivate/activate)

btw: Lock screen has no influence.

When I do "service network-manager restart" once (independent of network-manager state) I'm getting rid of the problem. After this I can do everything listed above without loosing the WiFi icon and I'm always able to see the wireless networks around.

As soon as I do any of this, it's back to default (meaning that next time you do anything of the listed actions above, the arrow icon will appear and you won't be able to see other wireless networks:
- reboot
- shut down and boot
- log out and log in

Again: Lock screen has no influence.