Hi ! Thank you for the answer

I got the error : NameError: global name 'active_id' is not defined

when I put it between '' no mistakes but doesn't work.

sorry, my bad. Try using self.env.context.get('active_ids') instead of active_ids.

Still doesn't work, i tried with self._context.get('active_ids') as well,replacing active_ids by active_id etc ...

Do I need to pass values trough context of my tree view ?

Yeah you need to pass that active_id in the context when clicking on the action in 'More' dropdown. which will be propagated to the "New" button action's context.

Is it automatically propagated ? because as i said in my original post, in the url the active_id on my second screenshot is the products i want to match with my label, but in the third screenshot the active_id is the label itself. so i'm scared that i can't use the active_id of the product anymore at this point.

Ok got some news :

def new_match(self):

context=self._context.copy()

if context.get('active_ids'):

context.update(default_products=[(6,0,context.get('active_ids'))])

else:

context.update(default_products=[(6,0,context.get('active_id'))])

return {

'name':_("Save a new matching"),

'view_mode': 'form',

'view_type': 'form',

'view_id': False,

'res_model': 'label.label',

'res_id': self.id,

'type': 'ir.actions.act_window',

'target': 'current',

'domain': '[]',

'context': context,

'flags': {'initial_mode': 'edit',},

}

with this action button, I manage to get the active_ids of my products in the 3rd screenshot. But still nothing filled where it should be. :)

Thank you again !