diff --git a/app/components/BookBuilder/Division.jsx b/app/components/BookBuilder/Division.jsx
index a26075a45ca98c84c6b75c58ffef36eaa71f5459..325c86b88e58a3adb46e464eeab30c6d766f9d65 100644
--- a/app/components/BookBuilder/Division.jsx
+++ b/app/components/BookBuilder/Division.jsx
@@ -142,7 +142,7 @@ export class Division extends React.Component {
           chapter={c}
           id={c.id}
           ink={ink}
-          key={c.index}
+          key={c.id}
           move={_onMove}
           no={i}
           outerContainer={outerContainer}