From Xojo Documentation
| This item was deprecated in version 2019r2.
Please use MenuItem.AddMenuAt as a replacement.
Inserts Item as a MenuItem at the position indicated by Index. Index is zero-based.
You can insert a Separator by passing the class constant MenuItem.TextSeparator.
The following example inserts a new item in the Edit menu with the text "Paste Special..." just below the Paste item.