Hello,
 
Its not possible with any Out of the Box K2 Features. May be you can try using JavaScript to achieve this.
 
Alternatively you can create an item view and place it on top of the editable list, show and hide based on button clicks in list view.
 
Regards,
Vijay.
 
                
     
                                    
            Hello Vijay,
 
Many thanks for your answer !
Unfortunately I am not a specialist in Javascript :-( 
Does anyone has a solution with JS? 
I have set up an Item View but I think it would be really convenient to be able to choose if you want to add a line at the top or bottom of the list. maybe in a future version of K2, it will be possible 🙂
 
Have a nice day !
Annick