Characters I typed in the Series Codex disappeared when I switched between "This book" and "Series". What happened?

"This book" and "Series" are two separate codexes, and in older versions switching between them, or closing the Codex, dropped anything not yet saved. From version 1.9.24, when something is not saved, BookyAI asks "Save your changes?" before you switch or close (with the X, a click outside the window or a link that leaves the Codex), with three choices: Cancel, Discard, or "Save and switch" (or "Save and close"). Characters and World are saved together. In an older version, press Save before you switch or close the Codex.