it uses the services of the framework for actually performing the navigation the tool container component manages the set of tools that are active while a specific activity is u201c current u201d the tool container provides a means for navigating between those tools u2014 e g it may use a tab cared model activities request the services of classes of tools thus there could be a tool that provides u201c window width and level control u201d the framework would have a registry of such mappings and when a specific activity is instantiated it registers its interest in these classes which the framework then arranges to have displayed when that activity is current the framework supports a process but any work is actually performed by the activities it contains some examples of the types of components that might be developed as activities include a component that provides basic 2d viewing of a study in the current shared data context the functionality would include layout control zoom and pan cine etc although the ui for these controls would be provided via tools a component that allows the user to enter a report perhaps including annotated images the completion of the report would be indicated by the user and would in turn signal.