Hi, 

thanks for your answer. Why does it override while I didn't made any relation between the new and the old one ? 

It's like if I created 2 box, given to 2 different people. But somehow, the box(old) given to the person A got no more access to a the sections he used to, while I just created/edited the box 2(new). And when I delete the box 2, the box one got back his possibilities..

Thanks for the checkox story, now I understand why rights came in a list.

For the third question, I got a form where I got a many2one field linked to another model to make it easy for the user, and avoid repeat the input. But for the new role created, when I make access to the model with the many2one field and try to create a new record, the many2one field is invisible. And I can create a new record even tho the many2one field is required

Hi,

If you override the existing group, access of the new group will be taken into action. Also check is there any record rules applying for the groups.

When the groups are independent, it will appear as checkboxes. If they are dependent (implied_ids) , it will appear as selection boxes.

Third question , can you describe it more ?

Hope it helps