title: Will NSUndoManager undo changes happening in the background?
body: <p>I've got an edit view controller which I'm using an NSUndoManager for which is the one set for my persistence store (core data project).</p>
  
  <p>One of the features of my app is synchronisation with an external server. What I want to know is, if I am editing something in my view, and at the same time the app is syncing itself with the server, if I change my mind and decide to undo any changes in my current edit, would it also undo all of the changes made during the sync if they were made whilst the undo grouping had started, or would it only undo changes I'd made myself?</p>