Commit https://github.com/odoo/odoo/commit/8caf84f70ada259f041b424d37686845604d182a was not handling the case where there was an invisible DOM element between the button box and the alert component. Let us clear all alerts. This commit also introduces a way to properly fix/extend bootstrap in future fixes/updates (some of our rules may already be moved in that file once it is forward-ported to master). closes odoo/odoo#27662