boarding

[kdmnet]

boarding and unboarding of passengers and cargo can leave you on the screen the text of the level of execution of the operations that can only be had for the moment by reactivating the menu

[virtuali]

That's exactly what has been explained at Pages 66-67 of the manual:

unless the toolbar ICON is ACTIVE ( white ), you can't see on-screen notifications, because they are handled by Javascript code and, for performance reasons, all Javascript code is killed by MSFS itself when the toolbar icon becomes inactive.