 // MARK: - GridColumn
 
 public class GridColumn {
+  public weak var gridView: GridView?
   public var leadingPadding: CGFloat = 0 { didSet { gridView?.updateGrid() } }
   public var trailingPadding: CGFloat = 0 { didSet { gridView?.updateGrid() } }
   // Note: NSGridColumn uses a non-optional CGFloat.leastNormalMagnitude as default

  let outerLayoutGuide = UILayoutGuide()
  let innerLayoutGuide = UILayoutGuide()
  var merged: [Range<Int>] = []

  private weak var gridView: GridView?

  init(gridView: GridView) {
    self.gridView = gridView

// MARK: - GridRow

public class GridRow {
  public weak var gridView: GridView?
  public var bottomPadding: CGFloat = 0 { didSet { gridView?.updateGrid() } }
  // Note: NSGridRow uses a non-optional CGFloat.leastNormalMagnitude as default
  public var height: CGFloat? { didSet { gridView?.updateGrid() } }
