In recent years, visual languages have become increasingly popular in the educational domain. But also researchers involved in other application domains are progressively looking at the potential of visual languages to make difficult tasks, as programming is, easier. In this paper we present the research we have conducted to provide end-users of a document management system with a visual language and the related editor by which to define content-based and context-aware rules. Rules are intended to be the proactive components of electronic documents and the visual rule editor we developed is aimed at empowering end-users and domain experts in making their documents more active with respect to both content, context and the users' interactions.