In the LXQt Configuration > Appearance > LXQt themes, switching between theeme
does not work for most, and works badly even for those that preview only after
clicking around.

This reminds me of a problem that has happened often in the past when the path
to the directory holding the themes is incorrect but back then there was a way
to define a path to the directory holding the themes. I don't see that now so
there is no way to manually correct the problem.

It should also be noted that if LXQt is chosen as the only Desktop installed
during installation (by first selecting Generic Desktop, then in the
Installation summary click on "Software" and then adding the LXQt pattern), the
generic openSUSE wallpaper displays instead of any of the LXQt themes, further
suggesting a bad path.