Same issue i update xubuntu 12.04 to 14.04 trusty. I fix adding "Indicator Panel" to the panel. In Spanish this is called "Complemento de indicador".
Source: http://askubuntu.com/questions/449658/networkmanager-tray-nm-applet-is-gone-after-upgrade-to-14-04-trusty
Same issue i update xubuntu 12.04 to 14.04 trusty. I fix adding "Indicator Panel" to the panel. In Spanish this is called "Complemento de indicador".
Source: askubuntu. com/questions/ 449658/ networkmanager- tray-nm- applet- is-gone- after-upgrade- to-14-04- trusty
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