A grid simulating muntins is retained or secured by clips within a spacer frame between glass sheets. The clips include a spacer-engaging member having a platform, and upright walls bendable toward one another, and a grid-engaging member. The grid-engaging member is mounted on the platform, extends upward between and spaced from the upright walls, and is received into one of the ends of the elongated members of the grid. The platform and portions of the upright walls of the spacer-engaging member are positioned within the spacer frame such that the ends of the elongated members of the grid are below the sight line of the unit. The spacer-engaging member and the grid-engaging member can be a monolithic piece, or the grid-engaging member can be detachably secured to the platform of the spacer-engaging member.