I have recently installed Odoo (version 8) and it is operating as expected, however, I have made some minor custimizations such as adding fields and changing labels names, all of these changes were made through web access as an Administrator (Settings>Technical>Database Structure>Models>hr.employee) and editing the FormView (activating the developer mode); and eventhough these changes seem to be persistent (I have opened Odoo using different web browsers and restarted the Odoo service) I cannot find the changes I made in the python nor XML files; I was expecting to see the XML files to be updated with the new fields or new labels.
Is this normal or is there some kind of feature that I have to activate?
Update: I upgraded the module hr.employee and as a result I lost all the customizations I had previously done.
Are the changes made through web access as Admin and editing the Formview not persistent??