As the number of public displays in the environment increases, new opportunities open up to improve situated interaction and to enable new kinds of applications. In order to make distributed display resources available to nomadic users, a key issue to address is how control can be dynamically shared between display users. It is important to study how control over a shared display can be acquired, released or shared by nomadic and residential users given their competing demands for display resources. In this paper, we present a system and a user study investigating these issues in the context of two applications both competing for display resources provided by a deployment of interactive office doorplates. The first application (Hermes II) provides situated note leaving and messaging services whereas the second one (GAUDI) supports user navigating a university department. Office occupants (i. e. residential users) can control whether the navigation application may (temporarily) use their doorplate display (thus giving priority to the navigation needs of nomadic users to the department). We report on findings from a user study, and discuss interface design implications for specifying display control.