/// <summary>
        /// If user does not have a forecastmonth registration
        /// the server will not return anytning.
        /// Generate "dummy" line, so missing registrations are visible
        /// </summary>
        /// <param name="month"></param>
        /// <param name="year"></param>
        /// <param name="response"></param>
        public virtual void TryAddMissingUsers(int month, int year, ForecastSearchResponse response)
        {
            var responsedUsersIds = response.ForecastMonths.Select(x => x.UserId).ToList();
            var requestedUserIds  = SelectedUsers.Where(x => !x.IsAllUsers).Select(x => x.UserId).ToList();
            var userEmptyResult   = requestedUserIds.Where(x => responsedUsersIds.All(y => y != x));

            foreach (
                var user in
                userEmptyResult.Select(userId => SelectedUsers.SingleOrDefault(x => x.UserId == userId))     // Select the local user-object
                .Where(user => user != null))
            {
                response.ForecastMonths.Add(new ForecastMonthDto
                {
                    UserId       = user.UserId,
                    UserName     = user.Name,
                    CreatedById  = 0,
                    Id           = 0,
                    IsLocked     = false,
                    Month        = month,
                    Year         = year,
                    ForecastDtos = new Collection <ForecastDto>()
                });
            }
        }