Thank you for you suggestion
. I have changed the code to add bookmarks into range instead of document. To keep it simple, I don't want to add the function inserting reference to heading outline number right now. Thank you again
.
Code:
Dim oldbm As Bookmark
Dim bmi As Bookmark
Dim bmShowHiddenOld As Boolean
bmShowHiddenOld = rg.Bookmarks.ShowHidden
'search for existing bookmark reference the same range
rg.Bookmarks.ShowHidden = True
For Each bmi In rg.Bookmarks
If bmi.Range.IsEqual(rg) And bmi.Name Like BookmarkPrefix & "#*" Then
Set oldbm = bmi
Exit For
End If
Next bmi
rg.Bookmarks.ShowHidden = bmShowHiddenOld