a window shade arrangement for motor vehicles that includes plastic injection molded guide rails designed such that they may be formed with injection tools that do not require moveable cores for forming guide grooves therein . in one embodiment , the guide rail includes an outer part formed with a guide groove and a support part made from less deformable material than the outer part for preventing widening of and deforming of the guide groove during usage . in another embodiment , the first and second molded parts are interconnectable to define the guide groove .