Our approach is based upon task analysis and scenario-based design, assuming that envisaged usage scenarios of reasonable quality are already available. Starting from them, we propose a systematic process for selecting user interface elements (in the form of widgets) in a few explicitly defined steps. This process provides a seamless way of going from scenarios through (attached) subtask definitions and various task classifications and (de)compositions to widget classes. In this way, it makes an important part of user interface design more systematic and conscious.

More precisely, we propose to explicitly assign subtask descriptions to the interactions documented in such a scenario, to the steps of both users and the proposed system to be built. Through combining those subtasks that together make up an interaction, interaction tasks are identified. For these, the right granularity needs to be found, which may require task composition or decomposition. The resulting interaction tasks can be classified according to the kind of interaction they require. From this classification, it is possible to map the interaction tasks to a class hierarchy of widgets. Up to this point, our process description is seamless, while the subsequent selection of a concrete widget is not within the focus of this work.