Running any program using Wine that puts an icon to the system tray and then trying to interact with it, does not work. To reproduce this, here's a tiny Windows executable called TurnFlash[1]. Its functionality (which is not relevant if it works or not), can be enabled or disabled by left clicking the icon in the systray, or it can be exited when opening a menu after you right click it.


STEPS TO REPRODUCE
1. Install Wine Staging (I didn't try regular Wine, plus I was able to reproduce this using Staging version 3.16 on both Arch Linux and Fedora)
3. Run "journalctl -f" on Konsole so we can monitor messages from plasmashell
2. Download and run the executable in a separate Konsole window: wine tflash.exe
3. No errors or warnings are thrown by Wine, but observe that a blue icon was added to the system tray
4. If we check journalctl now, an error similar to this one should be there:

Sep 26 22:04:54 archvm plasmashell[970]: QQuickItem::stackAfter: Cannot stack StatusNotifierItem_QMLTYPE_345(0x558c70156190, parent=0x558c6caa47b0, geometry=0,0 0x0) after StatusNotifierItem_QMLTYPE_345(0x558c6f4814c0), which must be a sibling

5. Try to interact with the icon by right clicking it (spamming the right click will only give multiple messages like this):

Sep 26 22:05:57 archvm plasmashell[970]: Could not find DBusMenu interface, falling back to calling ContextMenu()

6. Left clicking does nothing as well (it was supposed to change the icon to a different one), but nothing shows up in journalctl.
7. Hit Ctrl+C to interrupt the program running on Wine, this message should appear in the terminal:

Sep 26 22:09:36 arch plasmashell[970]: file:///usr/share/plasma/plasmoids/org.kde.plasma.private.systemtray/contents/ui/items/StatusNotifierItem.qml:104: ReferenceError: plasmoid is not defined


SOFTWARE VERSIONS
KDE Plasma Version: 5.13.5
KDE Frameworks Version: 5.50.0
Qt Version: 5.11.2


Thanks.


[1] https://www.nirsoft.net/utils/tflash2.html