Hi @refreshingdesign
It is possible that there is a bug at the moment which would prevent the load_field filter from working witha field name. Can you try using the field key instead?
In your filter, just change ‘name=select_waiting_list’ to ‘key=field_123’ – where this is the field key.
Also, you can check if the filter is working by placeing this code before the return $field;
print_r( $field );
die;
Thanks
E