Indexhibit Support

I'm developing a custom format with two custom options. This is the header:

1. /*
2. Format Name: Format Name
3. Format URI: domain.com/format/format_name/
4. Description: A new format.
5. Version: 1.0
6. Author: My name
7. Author URI: domain.com/
8. Params: format,custom('option1'),custom('option2'),
9. Source: exhibit
10. Objects: exhibits
11. */

The weird thing is that if I don't put a comma after custom('option2'), Indexhibit doesn't display option 2 in the Exhibit Options. Is this normal? I don't see it happening in the default formats.