title: Sorting NSTableColumn contents
body: <p>I have a problem with sorting NSTableColumn contents. In my NSTableView there are three columns: File, Size, Path. The contents are stored in NSMutableArray. Each object in this array is a NSDictionary containing three keys: file, size and path - value for each is a NSString. </p>
  
  <p>In Interface Builder, in each Table Column's attributes I can choose sorting options:
  Selector: IB entered "compare:" which I think is ok, because I compare NSStrings.
  Sort Key - and that's the problem I think - I don't know what to enter here. </p>
  
  <p>Any clues? If you've got questions about my code, please ask.</p>