Created attachment 129565 [details]
brokenmenus.png: the broken submenus (backgrounds blurred out for privacy)

SUMMARY
kate's menus are occasionally broken under GNOME 3, may pop up anywhere on screen. This happens both with Fedora's natively packaged kate 19.12.2, as well as FlatHub's kate 20.04.2.

STEPS TO REPRODUCE
1. Install GNOME 3 as packaged on Fedora 32 right now
2. Start a GNOME 3 Wayland session (not sure if it reproduces with the Xorg one, probably not)
3. Install & start kate from either flathub or repositories
4. Keep opening sub menus until issue appears, it happens around every 30% of the time

OBSERVED RESULT
See brokenmenus.png: the broken submenus in a screenshot showing the problem. (backgrounds blurred out for privacy) Also, the following shows up in the terminal output:
qt.qpa.wayland: setGrabPopup called with a parent, QtWaylandClient::QWaylandXdgSurface(0x55761166f0c0) which does not match the current topmost grabbing popup, QtWaylandClient::QWaylandXdgSurface(0x5576120f2d40) According to the xdg-shell protocol, 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 because xdg-shell mandate that child popups close before parents


EXPECTED RESULT
works / no menus placed kinda randomly on the screen

SOFTWARE/OS VERSIONS
Windows: 
macOS: 
Linux/KDE Plasma: Fedora 32 with GNOME 3.36.3
(available in About System)
KDE Plasma Version: 
KDE Frameworks Version: 
Qt Version: various, see flatpak/flathub release for one of them

ADDITIONAL INFORMATION