How do we learn conceptual modeling? What are common learning difficulties? Which tool support assists learners in what respect? The paper at hand reports on the design and development of a browser-based modeling tool integrated with a learning observatory in support of learning conceptual modeling and of studying the learning of conceptual modeling. Implementing a multi-modal data collection approach, the learning observatory tracks learner-tool interactions, records verbal data from learners and surveys learners about their learning processes to provide for analyses at the individual and aggregate learner levels in the quest for identifying patterns of learning processes, learning barriers and difficulties. We report on the current state of prototype development, discuss its software architecture and outline future development steps.