Thanks for your response, Devin. Just a very basic table style, similar to Twenty Fourteen would be fine. Tables are needed in posts and pages.
I opened the settings page, pressed the save button again and tested adding a comment. Once again, I get redirected to the wp-admin page.
Thanks for the quick response. I downloaded your patch, unzipped it, restarted httpd, checked plugin version (1.4.2.1) and tried posting comments, but was redirected to the wp-admin page still, unfortunately.
Hmmm, it seems, that assigning the language menus in the Appearance > Menus section makes things work. I consider this more like a work-around than a solution, though.
Visual is a beautiful theme for photography.