Hi, I hit a confusing bug caused by an interaction between Magritte cached descriptions and Gemstone's classHistory. I've a model component which define's it's own class side descriptionContainer: MyModel class descriptionContainer ^ super descriptionContainer componentClass: IZUIProjectEditor; yourself. However although I'd been changing code in IZUIProjectEditor, Magritte was holding onto an old version of my class causing unexpected problems: IZUIProjectEditor classHistory last asOop = IZProject description componentClass asOop "false" The solution I found was to flush the Magritte description cache: MADescriptionBuilder default flush Has anyone else had problems with updating code in Gemstone and Magritte cached descriptions? IZUIProjectEditor classHistory size = 6 How do I go about chasing down other references to old classes within Gemstone? Nick