Technological advancements and contemporary learning theories have redesigned the school environment to embed ICT technology in many aspects of the learning process. In particular, ICT technology can be exploited to monitor learners' behaviour during learning activities, for example to identify whether a learner is paying attention to the lecture. This poster presents the functional requirements of a visual tool for the smart classroom, which allows teachers to view and customize the attention monitoring subsystem for each individual student and for the classroom as a whole, in order to improve the educational process. Preliminary usability findings regarding its design are reported, as collected through a cognitive walkthrough evaluation with HCI experts.