A frame assembly for supporting a flat article. In one aspect, the frame assembly may include a stack including a transparent window panel and a frame. The frame may include a floor structure for supporting the stack and an outer annular wall coupled to and surrounding the floor structure, the outer annular wall including a plurality of corners, an outer surface defining a periphery of the frame, an inner surface defining a display cavity, and a front edge that defines a display opening configured to allow the stack to pass therethrough into the display cavity. The inner surface of the outer annular wall may include a plurality of recessed regions, each of the recessed regions encompassing one of the corners of the outer annular wall.