SUMMARY
Installed the Nextcloud client on KDE Neon, I follow the step until I have to choose a folder where to sync the files or accept the default one. Clicking on the button to choose another folder, it opens a window of the file manager (that's Dolphin, so I suppose that such window is part of Dolphin). The problem is that I can't interact with this window: nothing is clickable, there're no animation on mouse hover and the windows cannot be closed with the 'x' button on the title bar or with a combination such as Alt+F4.

STEPS TO REPRODUCE
1. Install Nextcloud Client
2. Authenticate on a server
3. At the step where you have to choose a folder, given "/home/user/Nextcloud" as default, click on the button to change the folder.

OBSERVED RESULT
The windows that opens is just unresponsive, nothing can be clicked and the window can't be closed with shortcuts or the "x" button.

EXPECTED RESULT
The window that is shown should let you pick a folder or create a new one.


SOFTWARE/OS VERSIONS
Linux/KDE Plasma: kernel: 5.4.0-67-generic
KDE Plasma Version: 5.21.2
KDE Frameworks Version: 5.80
Qt Version: 5.15.2

ADDITIONAL INFORMATION