public override void ItemDidExpand(NSNotification notification) { //var outlineView = (NSOutlineView) notification.Object; if (!notification.UserInfo.TryGetValue(NSObjectKey, out var value)) { return; } var node = value as MacObjectValueNode; if (node == null) { return; } node.HideValueButton = true; treeView.ReloadItem(node, false); treeView.ExpandNode(node.Target); }