Document.FormattingShowUserStyleName (Word)

Returns or sets a Boolean that represents whether to show user-defined styles.

This property corresponds to the Hide built-in name when alternate names exists check box in the Styles Gallery Options dialog box. Setting the FormattingShowUserStyleName property to True hides built-in styles when alternate user-defined styles exist. For example, if a user creates a heading style, such as Heading 1 or Heading 2, to take advantage of other built-in features of Microsoft Word, such as tables of contents, the user-defined style takes precedence, and the similarly named built-in style is not shown in the list of style names.

ActiveDocument.FormattingShowUserStyleName = True