diff --git a/docs/api.js b/docs/api.js
index 0debfa8c5..111cdd495 100644
--- a/docs/api.js
+++ b/docs/api.js
@@ -39,7 +39,7 @@ async function generateDocs () {
     ['modal_dialog/index.ts', 'modal_dialog.md'],
     ['rich_text_editor/index.js', 'rich_text_editor.md'],
     ['keymaps/index.ts', 'keymaps.md'],
-    ['undo_manager/index.js', 'undo_manager.md'],
+    ['undo_manager/index.ts', 'undo_manager.md'],
     ['canvas/index.ts', 'canvas.md'],
     ['canvas/model/Frame.ts', 'frame.md'],
     ['i18n/index.ts', 'i18n.md'],
diff --git a/docs/api/undo_manager.md b/docs/api/undo_manager.md
index 2e125b830..12acb6864 100644
--- a/docs/api/undo_manager.md
+++ b/docs/api/undo_manager.md
@@ -193,7 +193,7 @@ Note: New Components and CSSRules will be added automatically
 
 ### Parameters
 
-*   `obj`  
+*   `obj` **any** 
 *   `entity` **(Model | Collection)** Entity to track
 
 Returns **[Boolean][16]**