 import Cocoa
 
 class ConceptView: NSView, NSTextFieldDelegate {
-  let concept: Concept
+  var concept: Concept { didSet { needsDisplay = true } }
   var added = false
   let textField: NSTextField
   

  override func mouseDown(theEvent: NSEvent) {
    sprint("mouse down")
    concept.editing = true
    needsDisplay = true
  }
  
  override func sprint(message: String) {

    if canvas?.mode == .Concepts {
      if let concept = concept {
        concept.editing = true
      }
    }
    sprint("conceptView: mouse down \(concept?.identifier)")
