title: Xcode 4 "Clean" vs. "Clean Build Folder"
body: <p>You come at a certain point in the development of every app that what you see in the simulator does not match what you think should happen. Mostly these are human errors -- or at least they are in most of <em>my</em> cases ;-) -- but sometimes Xcode has just 'lost track', or so it seems. I've learnt that the <code>Clean</code> (Shift+Cmd+K) and <code>Clean Build Folder…</code> (Option+Shift+Command+K) menu options can show the difference between your error or Xcode's. </p>
  
  <p>My question though is:</p>
  
  <blockquote>
    <p>What does the <code>Clean</code> command do or not do, which leaves a reason for <code>Clean Build Folder…</code> to exist? When should I pick one over the other, why not just always clean the whole folder?</p>
  </blockquote>