Hi

I try to add properties to a PropertyGroup, the tab is created but the properties that i added to them is not showing in the correct tab thay all go to Generic Properties tab and if i look into the database at cmsPropertyType then propertyTypeGroupId is NULL for every properties that i added ? 

foreach (PropertyGroup propertyGroup in contentType.PropertyGroups.Where(x => x.Name == propertyTab.Name))
            {
                bool found = false;

                foreach (var type in propertyGroup.PropertyTypes)
                {
                    if(type.Alias == propertyType.Alias)
                    {
                        found = true;
                    }
                }

                if(!found)
                {
                    propertyGroup.PropertyTypes.Add(propertyType);
                }
            }

Im using the following namespaces:

using Umbraco.Core;
using Umbraco.Core.Models;
using Umbraco.Core.Services;
using Umbraco.Core.Models.PropertyType;