Fix #14994; that bug was introduced in #14228 (that was my fault).
~Also this commit explicit separates~ There are two functions of the tray icon:
- a system tray widget (
QSystemTrayIcon::isSystemTrayAvailable() == true
) - a high-level notificator via balloon messages (
QSystemTrayIcon::supportsMessages() == true
)
~These properties are mutually independent,~ e.g., on Fedora 29 + GNOME:
0QSystemTrayIcon::isSystemTrayAvailable() == false;
1QSystemTrayIcon::supportsMessages() == true;
UPDATE:
supportsMessages()
makes no sense without isSystemTrayAvailable()
: QSystemTrayIcon::showMessage()
just not working on Fedora 29 + GNOME.