title: How do you create NSWindow title bar to be transparent, but not the content of the window itself?
body: <p>I am in the process of creating a small image editor. 
  What I aim, is to create a window with transparent titlebar, but not what contains inside the window.</p>
  
  <p>I have check HUD Window, but it's really is a panel, not a window. And I am missing the regular close,maximize and minimize button.</p>
  
  <p>Is there anyway to create such window?
  Or can we modify HUD to hold regular close,max and min button?</p>
  
  <p>Thanks so much in advance!
  Eko</p>