protected override void CopyPropertiesFrom(FieldSetting source)
{
base.CopyPropertiesFrom(source);
var refFieldSetting = (ReferenceFieldSetting) source;
AllowMultiple = refFieldSetting.AllowMultiple;
Query = refFieldSetting.Query;
if (refFieldSetting.AllowedTypes != null)
AllowedTypes = new List<string>(refFieldSetting.AllowedTypes);
if (refFieldSetting.SelectionRoots != null)
SelectionRoots = new List<string>(refFieldSetting.SelectionRoots);
}