     guard results.count > 0 else { return nil }
     return results
   }
-  
   
   /// matchedConcepts: custom description
   ///

        canvasView.selectFromPoint = point
      } else {
        canvasView.selectToPoint = point
      }
      canvasView.needsDisplay = true
    default:

      didDragStart = false
      
    case .canvasWaiting:
      
      guard let selectionRect = canvasView.selectionRect else { return }
      // select concepts that intersect with the selection rect
      if let concepts = matchedConcepts(inRect: selectionRect) {
        safeTransiton {
          try stateManager.toMultipleSelectedElements(elements: concepts)
        }
      } else {
        for concept in document.concepts { concept.isSelected = false }
      }
      
      didDragStart = false
      canvasView.selectFromPoint = nil
      canvasView.selectToPoint = nil
      
      canvasView.needsDisplay = true
      
    default:
      return
    }
