A substrate treatment apparatus is provided. A method in accordance with an embodiment of the present invention includes: arranging a plurality of items into a plurality of groups, each group including at least two items; and selectively displaying each group in either an expanded state, wherein all of the items in the group are displayed, or in a collapsed state, wherein only a most recently used item of the group is displayed. The bars are spaced apart and extend parallel to the longitudinal sides of the section, are likewise at least substantially rectangular in cross-section and form, in the finished element, a feature providing security against rotation. This suppresses reduction in a data writing speed in mirroring and increases expandability.