On a panel frame 1 of a closure made of metal or plastic profiles, the grooved surface 4 has a guide channel 5 which is open on one side, but provided on both sides with undercuttings 6 in the crosswise direction for the accommodation of a connecting rod. The connecting rod found in guide channel 5 is coupled by the open side of the latter with a control mechanism, which has a pinion 14 that can be driven by an operating handle and is supported in a housing. In the region of incorporation of the control mechanism, the metal or plastic profile of panel frame 1 is provided with a notch 22, which penetrates the bottom 8 of guide channel 5 and in which is engaged the housing segment 15 of the control mechanism supporting pinion 14. At least one of the ends of a coupling slide bar 17 of longitudinally displaceable guiding housing segment 16 of the control mechanism permanently engaged with pinion 14 is supported in front of the open side of guide channel 5 on the metal or plastic profile. A rotating latch 24 is supported in the housing with axis parallel to the principal plane of pinion 14, and has projecting pieces or tabs 30a or 30b, the upper side of which is distanced from the rearward extending longitudinal edges of housing segment 16. In a first rotational position of rotating latch 24, the projecting pieces or tabs 30a or 30b are taken up flush by a recess 31a, 31b in housing segment 15 supporting pinion 14, while they are swung out in a second rotational position, projecting over the lateral surfaces of the housing segment 15, into the undercut region 6 of guide channel 5.