Version: EXTJS 4.0 pr 5

Issue: Windows that hide and are suppose to animate to an animateTarget produces errors in the javascript console.

Block of code below was extracted from gmap window example and modified to produce the error. Error is in ext-all-debug.js line 88042.

Ext.get('show-btn').on('click', function() {
        // create the window on the first click and reuse on subsequent clicks

            mapwin = Ext.create('Ext.Window', {
                layout: 'fit',
                title: 'GMap Window',
                closeAction: 'hide',
                animateTarget:  Ext.get('show-btn'),     //<---- this will cause the error
                x: 40,
                y: 60,
                items: {
                    xtype: 'gmappanel',
                    zoomLevel: 14,
                    gmapType: 'map',
                    mapConfOpts: ['enableScrollWheelZoom','enableDoubleClickZoom','enableDragging'],
                    mapControls: ['GSmallMapControl','GMapTypeControl','NonExistantControl'],
                    setCenter: {
                        geoCodeAddr: '4 Yawkey Way, Boston, MA, 02215-3409, USA',
                        marker: {title: 'Fenway Park'}
                    markers: [{
                        lat: 42.339641,
                        lng: -71.094224,
                        marker: {title: 'Boston Museum of Fine Arts'},
                        listeners: {
                            click: function(e){
                                Ext.Msg.alert({title: 'Its fine', text: 'and its art.'});
                        lat: 42.339419,
                        lng: -71.09077,
                        marker: {title: 'Northeastern University'}