Due to previous fix we don't need to sort individually any more

(see changeset 32f86f750e)

src/Umbraco.Core/Services/ContentService.cs

@@ -1030,7 +1030,7 @@ namespace Umbraco.Core.Services
                 }
 
                 //Look for children and copy those as well
-                var children = GetChildren(content.Id).OrderBy(x => x.SortOrder);
+                var children = GetChildren(content.Id);
                 foreach (var child in children)
                 {
                     Copy(child, copy.Id, relateToOriginal, userId);

src/Umbraco.Web/umbraco.presentation/umbraco/dialogs/sort.aspx.cs

@@ -78,7 +78,7 @@ namespace umbraco.cms.presentation
                     else
                     {
                         var children = contentService.GetChildren(parentId);
-                        foreach (var child in children.OrderBy(x => x.SortOrder))
+                        foreach (var child in children)
                             _nodes.Add(CreateNode(child.Id, child.SortOrder, child.Name, child.CreateDate, icon));
                     }
                 }

src/umbraco.cms/businesslogic/web/Document.cs

@@ -391,7 +391,7 @@ namespace umbraco.cms.businesslogic.web
         [Obsolete("Obsolete, Use Umbraco.Core.Services.ContentService.GetChildren()", false)]
         public static Document[] GetChildrenForTree(int NodeId)
         {
-            var children = ApplicationContext.Current.Services.ContentService.GetChildren(NodeId).OrderBy(c => c.SortOrder);
+            var children = ApplicationContext.Current.Services.ContentService.GetChildren(NodeId);
             var list = children.Select(x => new Document(x));
             return list.ToArray();
         }