I extended my book with more chapters, but the translated edition still has only the old chapters and the refresh button does nothing. How do I translate the new chapters?

Update to version 1.9.15, open the book and click the refresh icon (the circular arrow) on the edition's row in the Editions card once. In earlier versions an edition remembered the list of chapters the book had on the day the edition was created; chapters added later, for example with "Extend with AI", were never added to it, so the refresh button skipped them without saying anything. From 1.9.15 the edition takes over the new chapters before every translation run and translates only those. The chapters that were already translated are left exactly as they are. If everything is already translated, the refresh says so.