On a PS4 controller, there are two ways to scroll - the D pad and the right toggle. Both of these options simultaneously scroll from the top to the bottom of the loot items in the tent and hover over individual items, but only the most top/bottom visible items can be seen or taken. Any items in the middle of the loot section cannot be seen or taken. (On PC a player would use the mouse scroller, but the PS4 does not have this option)