Comment 6 for bug 1721534

The hp-systray command is commonly started as part of the session's autostart; for example, in Debian.

When it doesn't find a system tray on the current environment, it displays an error dialog box.

This is the case of GNOME which has dropped support for the system tray functionality in favour of a unified "notifications" functionality, pushing developers to quit relying on a system tray.

This comes from hplip/ui4/systemtray.py where QSystemTrayIcon.isSystemTrayAvailable() returns False when run under GNOME.

Solutions I see:
- Change the /etc/xdg/autostart/hplip-systray.desktop and add a property (NotShowIn, see https://specifications.freedesktop.org/menu-spec/latest/ar01s03.html) to not start in GNOME. It simply means adding this line: NotShowIn=GNOME;
- Change the hplip code to fail silently if it detects that there is no system tray. This might hide real issues however.
- Add a new dedicated binary package for hplip-gui-systray, and do not install it by default, especially for GNOME users.
- Understand the functionality of hp-systray and implement an alternative using GNOME's notifications; choose it when running in GNOME.