Learning management systems (LMS) are widely used in many educational environments. Although usability is widely acknowledged as a desired quality attribute, it has not been deeply investigated in the context of LMS systems where it has to align with pedagogy. In this research we evaluate extensions to an LMS designed to support the implementation of constructive alignment for technical units using a Task-Oriented Portfolio approach. The LMS application was extended with a range of open learner model-based visualisations to help staff and students monitor progress towards achieving unit intended learning outcomes throughout unit delivery. This paper reports on a case study of a formative usability testing of the prototype tool by using User eXperience (UX) metrics. The results unveil the potential usability issues and ways to improve the design of the prototype tool to better cater the actual target user needs.