Groups should not be nested in the view
Georg
If an object is added to GroupA and GroupB, but GroupB is not a child/parent of GroupA, it will currently be rendered as if GroupB is a child of GroupA (or vice versa)
Instead it would be better to render the object for each group separately (if it is a direct child)
This would be helpful for "deployment diagrams" where you want to show on which instances/servers an app is deployed for example.