Bug 482890

SUMMARY

When QT_QPA_PLATFORM=wayland is set, which seems to be the case for me by default (maybe since the latest update, or since i changed the QT wayland plugins I use), it is not posssible to see the popup sub-menus (sub-menus of file/edit/... like file->recently opened).

```
qt.qpa.wayland: Creating a popup with a parent, QWidgetWindow(0x616cf3bf5b40, name="MainWindow#1Window") which does not match the current topmost grabbing popup, QWidgetWindow(0x616cf58131c0, name="timelineWindow") With some shell surface protocols, this is not allowed. The wayland QPA plugin is currently handling it by setting the parent to the topmost grabbing popup. Note, however, that this may cause positioning errors and popups closing unxpectedly. Please fix the transient parent of the popup.
```

The error seems to be that a submenu popup sets it's parent as the main window instead of the menu, which seems to be not allowed on qt+wayland. If I run kdenlive manually setting the platform to x, I can see the popup menus just fine.

This is for all the submenus of the top bar, file/edit/..., for example file->recently opened.


STEPS TO REPRODUCE
1.  Open kdenlive with QT_QPA_PLATFORM=wayland
2.  Click file
3.  Click 'recently opened' : no submenu opens

(this is just an example, any submenu will do)

OBSERVED RESULT
no submenu opens

EXPECTED RESULT
the submenu opens

SOFTWARE/OS VERSIONS
Arch Linux
Qt Version: 
- local/qt5-base 5.15.12+kde+r151-1 (qt5)
- local/qt6-base 6.6.2-4
- local/qt6-wayland 6.6.2-1 (qt6)

ADDITIONAL INFORMATION
I'm using Gnome, and that might be part of the problem, although the log doesn't seem to reflect that. If it is gnome-related, and that is an unsupported use case for you, please let me know !
It happened just  after I installed QGnomePlatform/... so maybe it is related, but there also was a kdenlive update, so I'm not sure. If you can't reproduce without that, I guess it is the fault of that package, which is i think 'deprecated' as of now, so I guess it will stay that way.

Thank you for your time and awesome work !