don't show down arrow when no doc types

src/Umbraco.Web/Trees/ContentTypeTreeController.cs

@@ -20,6 +20,14 @@ namespace Umbraco.Web.Trees
     [CoreTree]
     public class ContentTypeTreeController : TreeController, ISearchableTree
     {
+        protected override TreeNode CreateRootNode(FormDataCollection queryStrings)
+        {
+            var root = base.CreateRootNode(queryStrings);
+            //check if there are any types
+            root.HasChildren = Services.ContentTypeService.GetAll().Any();
+            return root;
+        }
+
         protected override TreeNodeCollection GetTreeNodes(string id, FormDataCollection queryStrings)
         {
             var intId = id.TryConvertTo<int>();