In Studio 9.10 + the workflow model has changed so that workflow and task instances are deleted on completion. For this reason Workflow Commons uses the state change event handlers to maintain copies of these for its UI. However, when I look at the system information being retained it seems that while the system task instances are deleted on completion, the workflow instances are not and remain in the DB. Are they deleted later by some background job running? Further, I notice that if I create a new workflow (definition) in Studio Pro and then delete it, the definition still remains in the DB.