1) use the last codes in master that includes the documentation feature 2) create a hello world process that has a UserTask, e.g. StartEvent -> UserTask -> EndEvent 3) save the process 4) open the process. The exception above will be produced. On the other hand if we use a hello world process with another taks, like the NoneTask, no exception is produced. StartEvent -> NoneTask -> EndEvent As a quick test it was verified that if we comment the documentation page adding, in the class AbstractProjectDiagramEditor, the error is not produced any more. protected void initialiseKieEditorForSession(final ProjectDiagram diagram) { resetEditorPages(diagram.getMetadata().getOverview()); updateTitle(diagram.getMetadata().getTitle()); // comment this line -> addDocumentationPage(diagram); setOriginalHash(getCurrentDiagramHash()); hideLoadingViews(); onDiagramLoad(); }