In case of apps which are developed to support 'Resizable', it shows 18.5:9 automatically.
- App's maximum aspect ratio is set as over 18.5:9, it is operated as 'Full screen' mode (including games).
- App supports N OS and 'Resizable' function, it is operated as 'Full screen' mode (excluding games).
- Otherwise, it is operated as 'Conventional' mode (16:9)
User can convert to 18.5:9 aspect ratio in every each app and it is available to control in Display setting (Refer to below images)
(It is not available to set automatic ON/OFF for whole apps)