I'm now have a button but semmed me that this button do not works in edition mode

model examenes

informacion = html

model cita

test_info= html

xml

form

field where I want to show informacion called test_info

notebook

tree

button to send information

def show_test_information(self):        active_id = self._context('line_id')        print("activeee******************************************************************************",active_id)        self.test_info = self.test_id.informacion_examen

But this does not work in editable mode, I ask me if exist some event as onselect or something that allow me know the id of the selected item in the tree for can I send a information to a test_info.