We explore how the placement of control widgets (such as menus) affects collaboration and usability for co-located tabletop groupware applications. We evaluated two design alternatives: a centralized set of controls shared by all users, and separate per-user controls replicated around the borders of the shared tabletop. We conducted this evaluation in the context of TeamTag, a system for collective annotation of digital photos. Our comparison of the two design alternatives found that users preferred replicated over shared controls. We discuss the cause of this preference, and also present data on the impact of these interface design variants on collaboration, as well as the role that orientation, co-touching, and the use of different regions of the table played in shaping users' behavior and preferences. Author Keywords Tabletop interfaces, computer-supported cooperative work, co-located groupware, single display groupware. ACM Classification Keywords H5.3. Information interfaces...