diff --git a/docs/api/undo_manager.md b/docs/api/undo_manager.md
index 3fa12d85e..2e125b830 100644
--- a/docs/api/undo_manager.md
+++ b/docs/api/undo_manager.md
@@ -211,18 +211,6 @@ stack.each(item => ...);
 
 Returns **Collection** 
 
-## getStackGroup
-
-Get grouped undo manager stack.
-The difference between `getStack` is when you do multiple operations at a time,
-like appending multiple components:
-`editor.getWrapper().append(`<div>C1</div><div>C2</div>`);`
-`getStack` will return a collection length of 2.
-`getStackGroup` instead will group them as a single operation (the first
-inserted component will be returned in the list) by returning an array length of 1.
-
-Returns **[Array][17]** 
-
 ## clear
 
 Clear the stack
@@ -266,5 +254,3 @@ Returns **this**
 [15]: https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Object
 
 [16]: https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Boolean
-
-[17]: https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Array
diff --git a/src/undo_manager/index.js b/src/undo_manager/index.js
index eb222cda4..a3ffd218c 100644
--- a/src/undo_manager/index.js
+++ b/src/undo_manager/index.js
@@ -306,11 +306,12 @@ export default () => {
      * Get grouped undo manager stack.
      * The difference between `getStack` is when you do multiple operations at a time,
      * like appending multiple components:
-     * `editor.getWrapper().append(`<div>C1</div><div>C2</div>`);`
+     * `editor.getWrapper().append('<div>C1</div><div>C2</div>');`
      * `getStack` will return a collection length of 2.
      *  `getStackGroup` instead will group them as a single operation (the first
      * inserted component will be returned in the list) by returning an array length of 1.
      * @return {Array}
+     * @private
      */
     getStackGroup() {
       const result = [];