title: Xcode 4 shortcut for swapping focus between editor and assistant editor
body: <p>In Xcode, I am big fan of the assitant editor that shows me the corresponding .h or .m for the file that I am editing.</p>
  
  <p>Is there a shortcut that allows me to swap focus between this two windows? I frequently switch between the two and using the mouse every time is annoying.</p>