InlineModelAdmin show dropdown in Many to Many models

[Enrique Juan de Dios]

Hi everyone.

I'm newbie on Django and use Grappelli for admin site.

Files related: https://gist.github.com/1553188

When I use a one to many relation the admin shown this one:

But when I use many to many relation just had a drop down...

How I can transform the ugly drop down to a beautiful form like a one to many relation.

Thanks for your advice!