GMarkerDragendListener not found when upgrade from gmap-1.3.x to gmap-1.4.x

[新希望软件 -- 俞宏伟]

today, i want to upgrade my application from wicket-1.3.7 to wikcet-1.4.1,
i update wicket's core jar and wicketstuff's jar(build  from lastest code),
but i found that gmap2's GMarkerDragendListener class not found error.

here is my code using by GMarkerDragendListener class:
        gMarker.addBehavior(new GMarkerDragendListener() {

            @Override
            protected void onDragend(AjaxRequestTarget target) {
                lat = gMarker.getLagLng().getLat();
                lng = gMarker.getLagLng().getLng();

                target.addComponent(lblGlatLng);

                GInfoWindow gInfoWindow = gMap.getInfoWindow();
                gInfoWindow.open(gMarker, new
ShopAddressConfirmPanel(editShopAddressForm));
            }
        });