spring tongue 32 the divided shank 31 fits frictionally into the bore portion 29 when the clip element 26 is assembled with the muntin bar 23 the molded clip element 26 further includes at its forward end spaced approximately parallel spring legs 34 having inner side detent teeth 35 whose function will be described an arcuate crown portion 36 joins the tops of the spring legs 34 as best shown in fig7 the spring legs 34 project somewhat below the divided shank portion 31 as shown when the clip element 26 is placed in the recess 25 of the muntin bar 23 the two side wall portions 37 of the muntin bar 23 lie parallel to the spring legs 34 and thus prevent rotation of the clip element 26 in the recess of the muntin bar 23 the clip element 26 includes an internal wall 38 between the divided shank 31 and crown portion 36 and spring legs 34 fig4 notches 39 are provided on each clip element at the lower ends of the spring legs 34 a coacting molded plastics anchor element 40 for each clip element 26 is provided each anchor element 40 has a profiled end face 41 to match the opposing edge of the frame member 24 fig4 the opposite end face 42.