Scrolling and panning
If content on a screen extends beyond the viewing area, scroll arrows appear. Users can scroll by moving a finger on the trackpad, or, on BlackBerry devices with a touch screen, users can scroll by dragging a finger vertically across the touch screen. When users scroll, the movement of the content is proportional to the input rate of the motion. The quicker the motion, the faster the content on the screen moves. If a highlighted item moves out of view, the highlighted item moves back into view as scrolling decelerates.
Users can pan a picture, map, or web page by moving a finger on the trackpad, or, on BlackBerry devices with a touch screen, users can use a finger to drag the content on the screen. The content moves in the same direction and at the same rate that users move their finger.