Since [this commit], a horizontal scrollbar appears on mega menus. This is because Bootstrap position the dropdown automatically and the mega menus are a bit shifted on the right (due to a `translate3d` added by dynamic position of popper). This commit fixes the problem by removing dynamic positioning for mega menus. Steps to reproduce: - Have a system setting that enlarges the texts size or zoom the page - Have a mega menu - Open the mega menu => There is a horizontal scrollbar. [this commit]: https://github.com/odoo/odoo/commit/8689241f86e2d4ddb4e4510951f92b80e115b914 task-3133137 closes odoo/odoo#118842 Signed-off-by: loco-odoo <loco@odoo.com>