Starting on version 16.0, the HTML/CSS editor is very hard to resize. This is due to 16.0 introducing an iframe for the website: as soon as your mouse enters the iframe, the editor loses focus and cannot be resized anymore. This commit fixes that. task-3006138 closes odoo/odoo#120729 X-original-commit: e489abeffc72293544acb18eba23b52ed2224d60 Signed-off-by: Quentin Smetz (qsm) <qsm@odoo.com>