   }
 }
 
-fileprivate extension NSTreeNode {
+private extension NSTreeNode {
 
   var node: Node? {
     return self.representedObject as? Node

}

private let columnWidthRightPadding = CGFloat(40)

    self.triangleClosed = NSImage.fontAwesomeIcon(
      name: .caretRight,
      textColor: self.theme.directoryForeground,
      dimension: triangleImageSize
    )
    self.triangleOpen = NSImage.fontAwesomeIcon(
      name: .caretDown,
      textColor: self.theme.directoryForeground,
      dimension: triangleImageSize
    )

    self.lastThemeMark = theme.mark
