The UniForM workbench is an integration framework mainly geared towards tools for formal methods. It uses a simple, powerful and flexible notion of events to model all interactions between tools and users. In particular, the workbench provides HTk, an encapsulation of Tcl/Tk based on our event model (see HTk under Graphical User Interfaces). WWW: http://www.informatik.uni-bremen.de/uniform/wb/