w:unhideWhenUsed (Unhide Style When Applied)

Instructs an authoring application to remove the semiHidden flag from a style the first time the style is applied to content.

Parent elements

w:style

Description

w:unhideWhenUsed is a toggle element that, when set on a style, causes the authoring application to automatically remove w:semiHidden the first time the style is applied. After that initial use, the style becomes fully visible in the UI.

It is defined in ECMA-376 Part 1 §17.7.4.19.

w:unhideWhenUsed is almost always paired with w:semiHidden. Together they implement the “hidden unless used” behavior for Word’s internal styles like Default Paragraph Font.

Attributes

Attribute	Type	Possible Values	Description
`w:val`	`ST_OnOff`	`true`, `false`, `1`, `0`, `on`, `off`	Enables or disables the unhide-on-use behavior. Omitting `w:val` is equivalent to `true`.

Examples

<w:style w:type="character" w:styleId="DefaultParagraphFont">
  <w:name w:val="Default Paragraph Font"/>
  <w:uiPriority w:val="1"/>
  <w:semiHidden/>
  <w:unhideWhenUsed/>
</w:style>

using DocumentFormat.OpenXml.Wordprocessing;

var style = new Style(
    new StyleName { Val = "Default Paragraph Font" },
    new UIPriority { Val = 1 },
    new SemiHidden(),
    new UnhideWhenUsed()
)
{
    Type = StyleValues.Character,
    StyleId = "DefaultParagraphFont"
};

Notes

When the user applies the style for the first time, the authoring application should update the w:style element in styles.xml by removing w:semiHidden.
If w:unhideWhenUsed is present but w:semiHidden is not, it has no practical effect.