When you add a new component and edit a property of that component, if you then want to undo adding the component, you always have to first undo modifying the component and then undo adding the component. So you need two undo actions. It would be better to just combine them into one 'Add new component' undo action since it's no use to first be able to undo the rocket modifications, because you're then just left with a "virgin" component.