Usability of open source systems is becoming a relevant topic for investigation given the proliferation of open source software. General assumptions do not favor a positive relationship between the existing open source development model and good usability due to a host of social context reasons. In this paper we provide empirical evidence on this issue through a case study using an open source project called Ganttproject. Results point to likely deficiencies in the open source model. An analysis of this phenomena and some potential solutions for improving open source usability are proposed.