[xmonad] Not running my startupHook on restart

[Jakob Schöttl]

On 31.12.2015 09:06, Adam Sjøgren wrote:
> Brandon writes:
>
>>      as <- io getArgs
>>      when (null as) $ do
>>        {- your startup code here -}
> That worked great - thanks!
For me it does not work, I don't know why.

myStartupHook = do
     args <- io getArgs
     spawn $ "xmessage " ++ show (length args)
     ...

When I restart xmonad, xmessage pops up and shows "0". But `ps aux | 
grep xmonad` shows me the --resume option and the serialized state in 
the command line.

Any ideas?