Gtk.Widget.prototype.set_sensitive

function set_sensitive(sensitive:Boolean):void {
    // Gjs wrapper for gtk_widget_set_sensitive()
}

Sets the sensitivity of a widget. A widget is sensitive if the user can interact with it. Insensitive widgets are "grayed out" and the user can't interact with them. Insensitive widgets are known as "inactive", "disabled", or "ghosted" in some other toolkits.