The present invention relates to a window covering comprising a roller attached to a mounting device and an actuation device attached to the roller to rotate the roller in at least one of a first direction and a second direction. The window covering further comprises a front member having an upper portion attached to the mounting device; a second member with an upper portion attached to the roller such that rotation of the roller in the first direction winds the second member about the roller to retract it and rotation of the roller in the second direction unwinds the second member from the roller to extend it; and a plurality of pairs of ballast elements. Each ballast element is attached to one of the front member and the second member and positioned to engage the other member such that each pair causes or enables the front member to form a respective substantially traversal fold when the second member is wound about the roller to retract the front member to the retracted position, the folds being parallel to each other. According to an embodiment, the ballast elements of a same pair are be connected or joined to each other by a middle-connecting portion.