Fix notifications with xfce4-notifyd.

src/mainwindow.cpp

@@ -1167,7 +1167,15 @@ void MainWindow::showNotificationBaloon(QString title, QString msg) const {
   org::freedesktop::Notifications notifications("org.freedesktop.Notifications",
                                                 "/org/freedesktop/Notifications",
                                                 QDBusConnection::sessionBus());
-  if (notifications.isValid()) {
+  // Testing for 'notifications.isValid()' isn't helpful here.
+  // If the notification daemon is configured to run 'as needed'
+  // the above check can be false if the daemon wasn't started
+  // by another application. In this case DBus will be able to
+  // start the notification daemon and complete our request. Such
+  // a daemon is xfce4-notifyd, DBus autostarts it and after
+  // some inactivity shuts it down. Other DEs, like GNOME, choose
+  // to start their daemons at the session startup and have it sit
+  // idling for the whole session.
   QVariantMap hints;
   hints["desktop-entry"] = "qBittorrent";
   QDBusPendingReply<uint> reply = notifications.Notify("qBittorrent", 0, "qbittorrent", title,
@@ -1175,7 +1183,6 @@ void MainWindow::showNotificationBaloon(QString title, QString msg) const {
   reply.waitForFinished();
   if (!reply.isError())
     return;
-  }
 #endif
   if (systrayIcon && QSystemTrayIcon::supportsMessages())
     systrayIcon->showMessage(title, msg, QSystemTrayIcon::Information, TIME_TRAY_BALLOON);