Ubuntu 18.04 Gnome desktop does not have tray icon for qz-tray - why?

Question

I'm using qz-tray application installed/downloaded from GitHub: qzind/tray.

It does not show tray icon in Ubuntu 18.04 Gnome desktop.
What should I do to show it?

Answer 1

I ran the following commands to install QZ Tray (based on official guide):

sudo apt-get install git ant nsis makeself default-jre
cd ~/Downloads
wget https://github.com/qzind/tray/releases/download/v2.0.7/qz-tray-2.0.7.run
chmod +x qz-tray-2.0.7.run
sudo ./qz-tray-2.0.7.run

• At first I tested it in normal traditional desktop - Ubuntu MATE 18.04 LTS and it has tray icon in place here just after installation:

  

• Then I switched to Ubuntu 18.04 LTS with GNOME:

  1. With default settings it is not shown (i.e. gnome-shell-extension-appindicator is installed, enabled and loaded).
  2. Then installed TopIcons Plus extension from GNOME Software - it shows icon in non-expected place (note green printer near Firefox icon and black square near clock):

  

  1. Afterwards I removed TopIcons Plus and installed TopIcons extension - it does not work even if I start it manually with java -Xms512m -jar "/opt/qz-tray/qz-tray.jar".

So I recommend to drop this brave new GNOME world and switch to fully functional traditional MATE desktop environment by executing sudo apt-get install ubuntu-mate-desktop^.
As normal users we do not have time to overcome all these new non-predicted difficulties.
Also you can try to find support on GitHub issue page to fix this problem for GNOME.

Answer 2

Starting with 2.0.9, QZ Tray detects the absence of a System Tray and attached to the Taskbar icon instead.

Here's QZ Tray running on ElementaryOS:

Solutions including the System Tray compat libs (or avoiding Gnome entirely) are the correct solution for those using older QZ Tray versions, however those looking to use a newer version of QZ Tray no longer need to make special considerations. It should work out of the box.