Comment 4 for bug 1589798

Qt provides a cross platform class:
http://doc.qt.io/qt-5/qsystemtrayicon.html

But I am afraid this is somehow windows driven and using this will make Mixxx feel foreign running under GTK based Linux desktops.

Ubuntu Unity for example has a whitelist for systray icons, which avoids displaying cross platform systray icons

The Linux solution for your issue is implementing the MPRIS dbus interface.
This allows to use Mixxx in the same way you use Rhythmbox or Clementine form the systray (Sound Applet)

I have an unfinished branch to do that https://github.com/daschuer/mixxx/tree/mpris

How it the situation on Mac?