Examining case studies in design teaching and their analysis, we identify the role of structural activities and other solution searching activities in design learning and problem solving. The case studies follow students working on the same problem under two conditions - one group is taught using traditional face-to-face teaching while the other group is additionally supported by a text-based web board. The design activities of two students were followed in each condition through a semester, followed by in-depth interviews at the end of semester. The results show that cases with above average design work involved more structural activities than the mediocre cases. It also showed that design problem dissections are more organized in the better cases. These successful cases engaged in textual expression of their design solutions. Computer tools for design should therefore support multiple representations of design work.