title: how to detach an inner screen session
body: <p>I usually use gnu screen like this: 
     1. start a screen session for all my tasks
     2. When I login to a machine, I connect to a screen session (screen -x) made by my colleague (so this makes it an "inner screen")</p>
  
  <p>Problem is, when I need to detach from the "inner screen" via ":detach" command or ctrl+a+d, I get detached from my main screen (in #1). </p>
  
  <p>Is it possible to detach from "inner screen"?</p>
  
  <p>Thanks</p>