@klemensstrasser @jknlsn from what you've described I would say there's nothing to fix. Any changes to the ObservableObject must re-evaluate the whole hierarchy (even if your view is interested in only one property, say the selected tab).
As long as you're not doing anything expensive, these sort of re-evaluations are fine.
@phill @jknlsn Thanks! I also don't see any performance issues, but it just felt wrong!