An extendable cover for a portable electronic device including a first back panel having a first edge portion and a second back panel having a second edge portion. The first back panel and the second back panel being linearly slidable to move the first and second edge portions relative to each other along a sliding axis, wherein the first and second edge portions are opposite ends of the extendable cover along the sliding axis. The cover may include an electrical cable management arrangement having a rotatable hub disposed at the second back panel, and a hub-biasing mechanism coupled between the rotatable hub and the second back panel to bias the rotatable hub in a biased rotational direction to reel in a first electrical cable extending between the first back panel and the rotatable hub as the first and the second edge portions are moved towards each other.