Wifi icon is not displayed
Solution 1:
It could be very well possible that your nm-applet application has been killed or crashed.
Try running this command in a terminal:
nohup nm-applet &
if you don't want nohup.out file, you can use
nohup nm-applet > /dev/null &
Solution 2:
Run this command from the terminal, just copy and paste for accuracy.
sudo apt-get install --reinstall network-manager network-manager-gnome
This should work if you uninstalled the icon by mistake.
Solution 3:
this fixed it for me...
sudo apt-get install indicator-applet-complete