Event.onDOMReady(function() {

    var performanceBackground = function(evt) {
        var overlay = evt.event_data.data.sender;
    	var incoming = evt.event_data.data.incomingView;

    	if (incoming) {
    		if (incoming.id == 'performance') {
    			overlay.setOverlayShadowImageSrc('http://images.apple.com/macbook/images/overlay-performancebg20081014.png');
    		}
    	}
    }

    Event.Listener.listenForEvent(AC.ViewMaster, 'ViewMasterWillShowNotification', false, performanceBackground);

});