diff --git a/example/lib/pages/movable_background_image.dart b/example/lib/pages/movable_background_image.dart
index 23ef7163..a75000f2 100644
--- a/example/lib/pages/movable_background_image.dart
+++ b/example/lib/pages/movable_background_image.dart
@@ -379,8 +379,8 @@ class _MoveableBackgroundImageExampleState
                             editor.selectedLayerIndex < 0
                                 ? ReactiveCustomWidget(
                                     stream: rebuildStream,
+                                    key: key,
                                     builder: (_) => _bottomNavigationBar(
-                                      key,
                                       editor,
                                       constraints,
                                     ),
@@ -425,7 +425,9 @@ class _MoveableBackgroundImageExampleState
   }
 
   Widget _bottomNavigationBar(
-      Key key, ProImageEditorState editor, BoxConstraints constraints) {
+    ProImageEditorState editor,
+    BoxConstraints constraints,
+  ) {
     return Scrollbar(
       controller: _bottomBarScrollCtrl,
       scrollbarOrientation: ScrollbarOrientation.top,
diff --git a/lib/models/custom_widgets/custom_widgets_main_editor.dart b/lib/models/custom_widgets/custom_widgets_main_editor.dart
index 8a4cef44..e5a72f4e 100644
--- a/lib/models/custom_widgets/custom_widgets_main_editor.dart
+++ b/lib/models/custom_widgets/custom_widgets_main_editor.dart
@@ -102,6 +102,9 @@ class CustomWidgetsMainEditor {
 
   /// A custom bottom bar widget.
   ///
+  /// **IMPORTANT:** You must add the `key` to your bottombar widget that the
+  /// editor calculate layer movements correctly.
+  ///
   /// **Example:**
   /// ```dart
   /// bottomBar: (editor, rebuildStream, key) {