This is a common problem on Linux OS, as well as on Kylin OS (similar to Ubuntu).
    Kylin is our key client in China. When using QSystemTrayIcon, they need to get the system tray icon's geometry or hover event.
    Of course, geometry is not necessary if we can support hover event. When they hover on the icon, they want to popup a dialog.
    Kylin's desktop environment is a KDE-like DE. The Windows manager is based on kwin.  The system tray icon is based on SNI protocol.
    This is an image of Kylin, and you can install it just like you installed ubuntu: Kylin-Desktop-V10-SP1-HWE-Release-2203-X86_64.iso
   Thanks very much!