[Haskell-cafe] Weird thing happened when I use gtk2hs with concurrent.

This is the weird code, please see line 61. 20 cpuNew :: IO CPU 21 cpuNew = do 22   self <- meterNew 23   usage <- newIORef $ CPUusage 0 0 0 0 0 0 0 0 24   self `on` realize $ do 25     forkIO $ redraw self usage 33     return () 34   return self 35   where 56     redraw self usage = do 57       newUsage <- getUsage 58       oldUsage <- readIORef usage 59       postGUISync $ meterDraw self "Cpu" $ computeIdle $ diff newUsage oldUsage 60       writeIORef usage newUsage 61       threadDelay 10000 -- ten seconds, but it just refresh crazy! 62       redraw self usage