If you want to do this, then it is necessary to make sure `sub_entity._parent = None` afterward. I went back and forth about this for a long time and finally decided that the context-dependent properties like parent and transformations are better left as properties of the context (for you that would be the system; for me it is the event) rather than as properties of the entity. This is probably the central problem that led to the current event-centered design that I came up with.