This property is not used with any of the standard verbs provided with the Web Parts control set. When it is used with custom verbs, and the property value is set to true, a selected check box appears next to the verb to indicate the active status of the verb.

The purpose of this property is to give developers a way of indicating that some custom state associated with a verb is currently active. For example, suppose a developer creates a custom verb that enlarges the text size (for accessibility purposes) of the body text on all System.Web.UI.WebControls.WebParts.WebPart controls in a zone. If a user clicks the verb, this property value could be set to true, which would cause a selected check box to appear next to the Increase Text Size verb in the verbs menu, indicating to users that the state associated with the verb (enlarged text) is active.

This property cannot be set by themes or style sheet themes. For more information, see System.Web.UI.ThemeableAttribute and ASP.NET Themes Overview.