Odoo10 not updating model
I finally found the problem, it was due to an Indentation error.
When i added the field, i used linebreak in the editor, so it was at the same level of the other fields. But the editor used automatically tab when the other fields were indented with spaces.
It was that simple, but gave me a headache.
Odoo10 / Windows
I installed a module "my_app" in Odoo10, and want to change the model : app_model.py following this steps :

add field to app_model.py and save it
restart the odoo server form windows "services"
Activate developper mode
Update the application list
Upgrade the application

The problem is that when i open my app model in the configuration menu=>Database structure=>models , the added field doesn't appear
I tried to uninstall the app (to install it later with the new model), but Odoo didn't remove the app_model from the list of models (after app list update, restart service and even retart the server).
did i miss something ?