<para>The <seecref="M:Gtk.AppChooserButton.CustomItemActivated"/> event utilizes this delegate:</para>
<para>Event data is passed via the <seecref="T:Gtk.CustomItemActivatedArgs"/> parameter.</para>
<para>To attach a <seecref="T:Gtk.CustomItemActivatedHandler"/> to an event, add the CustomItemActivatedHandler instance to the event. The methods referenced by the CustomItemActivatedHandler instance are invoked whenever the event is raised, until the CustomItemActivatedHandler is removed from the event.</para>