volume buttons now controlling up/down, not volume

[carteriii]

My volume buttons on the side are now acting like the up/down action on a D-pad, moving the selection in any list up or down, or acting like a finger swipe up or down. Can anyone explain how I managed to do that, and perhaps more importantly how I get the volume buttons to go back to actually controlling the volume and displaying the volume screen (as shown in the manual, and how it used to be working)?