Comment 5 for bug 1542733

I'm also affected by this bug. After some (approx 5/6) disconnects and re-connects to wifi no problems but then later the wifi network name is not shown in network-manager applet. If I opt to connect to hidden network then the network name is available from the dropdown but after that is selected then the connect button is greyed out.

Ubuntu Mate 16.04 clean install i.e not an upgrade. Acer Aspire laptop. This same laptop was running Linux Mint Mate (on Ubuntu Precise base) and it did not have this problem.
I can run these as a manual workaround:

sudo killall nm-applet
sudo service network-manager stop
sudo service network-manager start
sudo nohup nm-applet -9

I also have a desktop running Linux Mint 14 Mate (Ubuntu base not Debian) which does not have this problem.