 }
 
 class CanvasView: NSView {
-  
   var delegate: CanvasViewDelegate?
   var mode: Mode?
-  var concepts = [Concept]() {
-    didSet {
-      sprint("concepts length: \(concepts.count)")
-      needsDisplay = true
-    }
-  }
-  var links = [Link]() {
-    didSet {
-      needsDisplay = true
-    }
-  }
-  var arrowStart: NSPoint? {
-    didSet {
-      needsDisplay = true
-    }
-  }
-  var arrowEnd: NSPoint? {
-    didSet {
-      needsDisplay = true
-    }
-  }
+  var concepts = [Concept]() { didSet { needsDisplay = true } }
+  var links = [Link]() { didSet { needsDisplay = true } }
+  var arrowStart: NSPoint? { didSet { needsDisplay = true } }
+  var arrowEnd: NSPoint? { didSet { needsDisplay = true } }
+  var clicks = [NSPoint]() { didSet { needsDisplay = true } }
   var originConceptIdentifier: Int?
   var targetConceptIdentifier: Int?
   

  
  override func mouseDown(theEvent: NSEvent) {
    sprint("canvasView: mouse down")
    for concept in concepts {
      concept.editing = false
    }

    if mode == Mode.Concepts {
      for concept in concepts { addConceptView(concept) }
    }
    
    for point in clicks { drawCenteredDotAtPoint(point, color: NSColor.cyanColor()) }
  }
  
  // MARK: - Drawing Functions
