a stationery accessory system comprises a slidable tab including indicia of contents contained in or demarcated by the stationery accessory system and a sheet - like member including a rail ; one of the slidable tab and the rail having a channel defined along a longitudinal aspect thereof , the channel defined by a wall of the rail , and the channel having a longitudinal opening narrower than a width interior to the channel measured parallel to the longitudinal opening ; and the other of the slidable tab and the rail having an expanded edge , the expanded edge having a width greater than the longitudinal opening such that the channel and the expanded edge are slidably engageable .