title: Can IntelliJ IDEA open more than one editor window for files from the same project?
body: <p>I can split editor panes horizontally or vertically, but it does not seem possible to view code in two separate physical windows.  I am aware that Idea can open multiple <strong>projects</strong> in separate windows, but I'd like to be able to do this for two files in a <strong>single</strong> project.  </p>
  
  <p>One answer suggested unpinning the tab, but I haven't been able to make that work (I'm on Mac OSX if that matters.)</p>
  
  <p>This seems like a basic feature in today's world of multi-headed workstations.  Before moving to an IDE I used to do this regularly with good old Emacs.  Is there some trick I am not aware of to make this happen?</p>