In the backend, when a mailing popup was being edited, it was not centered in the edition area (and went under the editor UI) and was not using the correct style. task-2083465 closes odoo/odoo#38449 X-original-commit: 6ccf3b618b4b0774deccb4f75bf33f3ea4dc8b75 Signed-off-by: Quentin Smetz (qsm) <qsm@odoo.com>