Fixes U4-9437

src/Umbraco.Web/Trees/ContentTreeControllerBase.cs

@@ -125,9 +125,10 @@ namespace Umbraco.Web.Trees
             // use helper method to ensure we support both integer and guid lookups
             int iid;
 
-            // if it's the root node, we won't use the look up
-            if (id != "-1")
+            // look up from GUID if it's not an integer
+            if (int.TryParse(id, out iid) == false)
             {
+
                 var idEntity = GetEntityFromId(id);
                 if (idEntity == null)
                 {
@@ -135,10 +136,6 @@ namespace Umbraco.Web.Trees
                 }
                 iid = idEntity.Id;
             }
-            else
-            {
-                iid = int.Parse(id);
-            }
 
 
             //if a request is made for the root node data but the user's start node is not the default, then