Unix & Linux Stack Exchange is a question and answer site for users of Linux, FreeBSD and other Un*x-like operating systems. Join them; it only takes a minute:

Sign up
Here's how it works:
  1. Anybody can ask a question
  2. Anybody can answer
  3. The best answers are voted up and rise to the top

In an evergoing battle against an ugly icon, I found that applications can communicate with the system tray by sending X client messages. Is there a utility for spying on these messages?

share|improve this question
up vote 5 down vote accepted

Run the application under xtrace. It'll log all communications between the application and the X server, including the command to send or receive an X client message.

xtrace myapp
share|improve this answer
That's kind of what I'm trying to solve - what application is putting that there? I have the class window class name: gnome-power-manager, but there is no aplication called that. There is nothing matching "power" running as a daemon. – Shawn J. Goff Jun 24 '12 at 1:14
@ShawnJ.Goff Trace the server side, i.e. the system tray. – Gilles Jun 24 '12 at 1:18
Oh, and are you sure that the communication is via window events and not via dbus? – Gilles Jun 24 '12 at 1:19
@ShawnJ.Goff gnome-power-manager is nowadays part of gnome-settings-daemon – Ulrich Dangel Jun 24 '12 at 5:22


    xev -id WINDOW_ID

will print X11 "window events". In X11, these things are called "events". (As opposed to "messages" in Microsoft Windows).

To obtain window id, use xwininfo.

man xev, man xwininfo.

share|improve this answer
A [client message][1] seems to be a type of event. The freedesktop [system tray spec][2] specifically talks about an "x client message". In any case, I have the correct window, but xev is not giving my any information about what program is sending what event to that window, but its status is definitely being updated by something. [1]: tronche.com/gui/x/xlib/events/client-communication/… [2]: standards.freedesktop.org/systemtray-spec/… – Shawn J. Goff Jun 23 '12 at 21:59

Your Answer


By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.