Description of problem:

Ever since the upgrade from LibreOffice 7.2.5.2 to LibreOffice 7.3.2.2, LibreOffice has been unable to properly display dropdown menus in Plasma Wayland (it works fine in GNOME Wayland and Plasma X). As a workaround, you can start it from the command line using "QT_QPA_PLATFORM=xcb libreoffice", which forces it to run on XWayland (but we can't expect the average user to figure out something like this).

When running LibreOffice 7.3 on Plasma Wayland, if no popup windows are currently open, then attempting to open a dropdown menu will result in the dropdown being displayed in the centre of the screen, instead of being displayed in the position it should appear (see the attached screenshots for an example). Furthermore, the dropdown menu appears as a window in the Plasma task manager, titled "soffice.bin".

If a popup window (for example, the "Print..." dialog) is currently open, then the dropdown menu (and the associated "soffice.bin" window) will appear for a split second, only to disappear, making it unusable.

This renders many features of LibreOffice unusable in Plasma Wayland (unless started with "QT_QPA_PLATFORM=xcb") - for example, it's impossible to switch to a different printer in the "Print..." dialog.

This issue does NOT affect File/Edit/View/etc. menus, or the dropdown menus in the Open or Save dialogs (presumably because the Open and Save dialogs are provided by Plasma, rather than by LibreOffice).

Perhaps a section should be added to the Mageia 8 Errata, advising Plasma Wayland users to start LibreOffice using "QT_QPA_PLATFORM=xcb libreoffice"?

Version-Release number of selected component (if applicable):

7.3.2.2-1.mga8

How reproducible:

Always (as long as you are using Plasma Wayland, and NOT using "QT_QPA_PLATFORM=xcb")

Steps to Reproduce:

1. Make sure you have the "plasma-workspace-wayland" package installed, and install it if you don't already have it
2. When logging in from your Display Manager, make sure to select "Plasma (Wayland)" as your session (tested in SDDM and GDM - "Plasma (Wayland)" may not be available in lightweight Display Managers)
3. Open LibreOffice Draw (note all LibreOffice applications are affected - I just designed these steps for Draw)
4. In the "Properties" panel to the right, attempt to open any of the dropdown menus (you may need to click several times to get it to open), and observe what happens
5. In the top-left, open the "File" menu, and select "Print..."
6. Attempt to open any of the dropdown menus, and observe what happens

Actual results:

When opening dropdowns in the "Properties" panel, the dropdown appears in the centre of the screen, and a window titled "soffice.bin" appears in the task manager. When attempting to open dropdowns in the "Print..." dialog, they don't stay open.

Expected results:

All dropdown menus should open after only one attempt at clicking on them, should not instantly disappear, and should not spawn a window in the task manager.