Open the terminal type “sudo edit /etc/NetworkManager/nm-system-settings.conf” change the “managed=false” to “managed=true” and then save it.
then in the terminal type “killall nm-system-settings”
and then reboot.
Method 2
right click panel>add to panel>Notification Area
منبع :http://www.forum.persianadmins.ir/showthread.php?t=15975&highlight=panel