An action that closes the screen it belongs to — a sheet, or the launch's
splash — and succeeds with the handle now on top (undefined when the stack
is empty). It is back over the screen's own handle, refused when the screen
is not on top. A screen uses it where the app closes the screen itself: the
451 launch's NDX screen's close edge, which is navigation only.
An action that closes the screen it belongs to — a sheet, or the launch's splash — and succeeds with the handle now on top (
undefinedwhen the stack is empty). It isbackover the screen's own handle, refused when the screen is not on top. A screen uses it where the app closes the screen itself: the 451 launch's NDX screen's close edge, which is navigation only.