Updated predicate to use GetParentAlias()

Author: ronaldbarendse

src/Umbraco.Web/PropertyEditors/NestedContentController.cs

@@ -1,5 +1,6 @@
-using System.Collections.Generic;
+using System.Collections.Generic;
 using System.Linq;
+using Umbraco.Core.Models;
 using Umbraco.Core.Services;
 using Umbraco.Web.Editors;
 using Umbraco.Web.Mvc;
@@ -22,7 +23,7 @@ public IEnumerable<object> GetContentTypes()
                     name = x.Name,
                     alias = x.Alias,
                     icon = x.Icon,
-                    tabs = x.CompositionPropertyGroups.Where(y => y.Type == Core.Models.PropertyGroupType.Group && !y.Alias.Contains("/")).Select(y => y.Name).Distinct()
+                    tabs = x.CompositionPropertyGroups.Where(x => x.Type == PropertyGroupType.Group && x.GetParentAlias() == null).Select(y => y.Name).Distinct()
                 });
         }
     }