Why aren't certain indicators showing in Unity?

Solution 1:

The older system tray has been retired since 10.04 and has now been totally removed in 13.04. pyalienfx needs to use the appindicator, you can file a bug on the program and point to this page:

  • https://wiki.ubuntu.com/DesktopExperienceTeam/ApplicationIndicators

So that app authors can port their application. This includes a fallback option so the software will still work in older Ubuntus and other distros.

As far as pidgin and thunderbird, those are integrated into the messaging menu (The little envelope).

Here are some other pointers:

  • How do I migrate from systray to AppIndicators?

Solution 2:

Here's my solution:

How to re-enable the systray whitelist in Ubuntu 13.04 (Raring Ringtail)

If you use such an application and want the systray whitelist back in Ubuntu 13.04, you can use a PPA that comes with Unity patched to re-enable the systray whitelist. To do this, open a terminal and run the following commands:

sudo add-apt-repository ppa:timekiller/unity-systrayfix
sudo apt-get update
sudo apt-get upgrade

Then, restart Unity by pressing ALT + F2 and entering "unity" or by logging out. Then open Dconf Editor, navigate to com > canonical > unity > panel and the "systray-whitelist" should be displayed there so you can enable some apps to be able to use the systray.

After adding an application to the systray whitelist, remember to restart Unity or else it won't work.

source: http://www.webupd8.org/2013/05/how-to-get-systray-whitelist-back-in.html