Flexicious expandAll with children function

Question

I use the new option getChildrenFunction to create my grid. All work fine and manuel expand of all level work fine but when I can't expand All levels(with grid.expandAll()) it stop one level before the end. How can I do ? Here my children function :

private function getCustomChildren(object:Object,level:FlexDataGridColumnLevel):Object
            {
                if(object is Flow && ExplorationManager.getInstance().suggestionsXML != null)
                {
                    var wrappedKeyParamXML:ArrayCollection = new ArrayCollection;
                    for each (var xml:XML in ExplorationManager.getInstance().suggestionsXML..keyParameter)
                    {
                        wrappedKeyParamXML.addItem(new XMLWrapper(xml.copy(),object.id,xml.length()));
                    }
                    return wrappedKeyParamXML;
                }
                else if(object is Element)
                    return object.children;
                else if(object is XMLWrapper)
                {
                    return object.children;
                }   
                else 
                    return null;
            }

Thanks for answer