diff --git a/Tk.xs b/Tk.xs
index 61070650..5bee43f1 100644
--- a/Tk.xs
+++ b/Tk.xs
@@ -1028,6 +1028,8 @@ CODE:
   Lang_CmdInfo *info = WindowCommand(win,NULL,3);
   RETVAL = Tk_Grab(info->interp,info->tkwin,global);
  }
+OUTPUT:
+ RETVAL
 
 SV *
 Widget(win,path)