Problem with this button GET TOTAL: I got a form that has a one2many relationship with the other class, when I go to the tree view of this one2many the button GET TOTAL is disabled but when in the original form view it is enbled, I think the cuase of this is the widget one2many because i tried it to many2many it works but i need it in one2many relationship. any idea please or have you encountered this kind of problem?? how can i fix this problem??
the form that has a one2many relationship and the button disabled:

Please post your Code! xml and py.