Shared window systems have become a popular vehicle for supporting distributed, synchronous collaboration. A t present they are diflcult to build and they support limited paradigms of multi-user interaction with shared applications. We believe this dificulty as largely due to the inverted nature of the client/server architecture of most distributed window systems. The architecture is inverted in the sense that the user is nearer the server than the client; this hampers attempts to share windows. By comparing the traditional client/server architecture of distributed j l e systems with the inverted architecture of distributed window systems we argue that it is possible to develop window systems where the user is nearer window system clients than servers, and that this architecture greatly facilitates the sharing of windows among users.