Why does a tab in the Maker show a lock?

In the Event Hub Maker every part has the same four tabs: Edit, Style, Background and Animate. A tab with a 🔒 has nothing to set on that part. Tap it anyway: the rows say the problem and where it is set instead — a line on the cover takes its background from the Cover Scene, and one tap selects it. The camera keeps one style for every guest, so its Style is locked too.

This part of Setnayan is not included in the app.