public void UserSelected(object obj)
        {
            if (SelectedUser == null)
            {
                return;
            }

            if (SelectedUsers.Count(u => u.User.UserID == SelectedUser.UserID) == 0)
            {
                if (_timeEntryFilter != null)
                {
                    _timeEntryFilter.AddUser(SelectedUser);
                }
                SelectedUsers.Add(new UserFilterViewModel(SelectedUser));
                OnPropertyChanged("SelectedUsers");
                OnPropertyChanged("HasConsultants");
            }
        }