public void ExecuteLazyCommand()
        {
            DTE dte   = Package.GetGlobalService(typeof(DTE)) as DTE;
            int?index = DteHelper.GetDocumentIndex(dte.ActiveDocument.FullName);

            if (index == null)
            {
                return;
            }
            if (index == 1)
            {
                index = dte.Documents.Count + 1;
            }

            for (int i = (index ?? 0) - 1; i >= 1; i--)
            {
                try
                {
                    dte.Documents.Item(i).Activate();
                    break;
                }
                catch { }
            }
            //dte.ExecuteCommand("View.NavigateForward", "");
        }