Thanks! Than everything is fine!
This free plugin manages that very well: https://yoast.com/wordpress/plugins/duplicate-post/
At the third tab, Display, you can choose lists and than you see the duplicate function at the Bulc actions. I forgot I used this plugin at another site, where those bulk actions were displayed..
After deleting the license code, saving, and adding it again, now I get a green text : receiving updates” and the license seems to be accepted. But still I do not see the extra facilities, like copying a list. Helas