Found out how to get there. I used to get to the nozzles section only via the edit zone, and then select the nozzle. That's where I did press the 'add' button.
I just noticed from the main menu you can get to the customs nozzle section.
It would be good that from the select nozzle section, there is a link to the custom nozzles. And only in one place you can add and delete them.
Currently there are now 2 places where you add nozzles, but one place where you can remove nozzles. That's where my confusion started.
All solved now.