public void RegisterAnchor(Region.Anchor anchor) { Region target = anchor.GetRelativeElement(); Region source = anchor.GetElement(); if (target == null) { // anchor off of the top level if (!topElements.Contains(source)) topElements.Add(source); return; } if (!anchorLinks.ContainsKey(target)) anchorLinks[target] = new List<Region>(); List<Region> sourceList = anchorLinks[target]; if (!sourceList.Contains(source)) sourceList.Add(source); }