Im using compositefield, but I'm getting some problems with validation message. When I set msgTarget : 'qtip', message error is not show it.

Is this a bug?

Code:
var form = new Ext.form.FormPanel({
        renderTo: 'docbody',
        title   : 'Composite Fields',
        autoHeight: true,
        width   : 600,        
        bodyStyle: 'padding: 5px',
        defaults: {
            anchor: '0'
        },
        items   : [{
                xtype     : 'textfield',
                name      : 'email',
                fieldLabel: 'Email Address'
            }, {
                xtype: 'compositefield',
                fieldLabel: 'Date Range',
                msgTarget : 'qtip',
                anchor    : '-20',
                defaults: {
                    flex: 1
                },
                items: [{
                        xtype     : 'datefield',
                        name      : 'startDate',
                        fieldLabel: 'Start'
                },{
                        xtype     : 'datefield',
                        name      : 'endDate',
                        fieldLabel: 'End'
                    }
                ]
            }
        ]
});