expression.ShowHidden
expression Required. An expression that returns a Bookmarks collection object.
Remarks
Hidden bookmarks are automatically inserted when cross-references are inserted into the document.
Example
This example displays the Bookmark dialog box with both visible and hidden bookmarks listed.
ActiveDocument.Bookmarks.ShowHidden = True
Dialogs(wdDialogInsertBookmark).Show
This example displays the name of each hidden bookmark in the document. Hidden bookmarks in a Word document begin with an underscore ( _ ).
ActiveDocument.Bookmarks.ShowHidden = True
For Each aBookmark In ActiveDocument.Bookmarks
If Left(aBookmark.Name, 1) = "_" Then MsgBox aBookmark.Name
Next aBookmark