Problem --------- When you go in the settings -> layout (debug mode) -> select external layout --> preview document a traceback appears due to infinite looping in the view definitions. Solution --------- This field is highly technical and should not be fiddled with by users. For such reason, we set it as `readonly`. task-3479152 closes odoo/odoo#136399 X-original-commit: 03cffc460e620639db6dbe132aa0be073a6396f5 Signed-off-by: Quentin De Paoli <qdp@odoo.com> Signed-off-by: Antoine Boonen (aboo) <aboo@odoo.com>