It is tragedy to upgrade my ubuntu box before it actually release. The new desktop environment – Unity, which was used in netbook Ubuntu version previously makes a new experience but with more missing thing. For example, the notification area icons are blacklisted via some reason (Farewell to the notification area).
The solution to solve it is simple, just settings via some commands, the reference is from How to re-enable notification area applets in Ubuntu 11.04. The commands are:
1. Get your current settings via:
$ gsettings get com.canonical.Unity.Panel systray-whitelist
And the result will like
['JavaEmbeddedFrame', 'Mumble', 'Wine', 'Skype', 'hp-systray']
2. Modify it w/ adding gcin, like:
$ gsettings set com.canonical.Unity.Panel systray-whitelist "['JavaEmbeddedFrame', 'Mumble', 'Wine', 'Skype', 'hp-systray', 'gcin']"
3. Relogin and the tray icon shown. 🙂
P.S if it is no work, retype the command via root, it may help.
Thanks for the people for help in thread on gcin forum.