The son are not independent. The set consists only of a single threaded through the retractor. Therefore it is IMPOSSIBLE, how it is designed to have the 5 strained son (and it has nothing to do with straight walls or not). He had to remove the right side with a screwdriver, cut the son to make them independent and make a knot at each end to be able to adjust them properly. Why the designers did not they think their roller in this way from the beginning? Mystery ...
