protected override void DragMoveEvent(Qyoto.QGraphicsSceneDragDropEvent arg1)
 {
     if (arg1.MimeData() is RosterItemMimeData <T> )
     {
         arg1.Accept();
     }
     else
     {
         arg1.Ignore();
     }
 }
            protected override void DropEvent(Qyoto.QGraphicsSceneDragDropEvent arg1)
            {
                if (arg1.MimeData() is RosterItemMimeData <T> )
                {
                    arg1.Accept();

                    ItemOver = false;

                    var mimeData = (RosterItemMimeData <T>)arg1.MimeData();
                    var oldGroup = (RosterItemGroup)mimeData.Item.ParentItem();

                    var editableModel = (IAvatarGridEditableModel <T>)m_Grid.Model;
                    editableModel.AddItemToGroup(mimeData.Item.Item, this.Name);
                    if (arg1.DropAction() != Qt.DropAction.CopyAction)
                    {
                        editableModel.RemoveItemFromGroup(mimeData.Item.Item, oldGroup.Name);
                    }
                }
                else
                {
                    arg1.Ignore();
                }
            }