when starting “qt5 settings” from the application menu there is an application error msg stating “The QT_QPA_PLATFORMTHEME environment variable is not set (required values: qt5ct or qt6ct).”
Where would I set this?
thx dan

Do you have the package qtwayland5 installed? Or qt6-wayland for QT6?

Hi Josch,
Just did sudo apt install qt6-wayland and rebooted → no change

and same if I remove and instead apt install qtwayland5

What happens if you start your application with QT_QPA_PLATFORMTHEME=qt5ct set?

qt5ct is a peculiar application that, to have an effect, requires this variable to be set globally in your profile.

Ok - I put export QT_QPA_PLATFORMTHEME=qt5ct in .bashrc. Now, if i call qt5ct from the command line it works. Selecting QT5 Settings from the application menu still does not work.

Try adding it to /etc/profile and completely log out and in again.