Single Display Groupware (SDG) supports face-to-face collaborators working over a single shared display, where all people have their own input device Although SDG is simple in concept, there are surprisingly many problems in how interactions within SDG are managed One problem is the potential for interference, where one person can raise an interface component (such as a menu or dialog box) in a way that hinders what another person is doing i.e , by obscuring another person's working area that happens to be underneath the raised component. We propose transparent interface components as one possible solution to interference, while one person can raise and interact with the component, others can see through it and can continue to work underneath it To test this concept, we first implemented a simple SDG game using both opaque and transparent SDG menus. Through a controlled experiment, we then analysed how interference affects peoples' performance across an opaque and transparent...