On the toolbar below, piano and violin open, but only guitar has a lock. Is it broken?
This isn’t a bug — it’s a feature tied to your subscription. The Guitar window opens on a subscription account, while Piano, Violin, and Recording are available even on a free account.
Either window shows the current scale. When you open the piano, the notes of the scale light up, with the tonic in orange. The guitar and violin show note positions on the fretboard the same way.