Bug 1696718 landed a fix to propagate the position change from layout. However that's not correct, because the widget isn't resized until nsView::ProcessPendingUpdatesForView is resized (and even that in some platforms it might be async). So the right place to propagate the position change is in nsXULPopupManager (which we call into from the view system which listens itself to the widget). Let's try to enable the test for that bug everywhere with this fixed. Differential Revision: https://phabricator.services.mozilla.com/D127801