Forge, install SSL, "Automatically Add Intermediate Certificates" What?

I'm trying to install a SSL certificate via Forge. I've clicked installed and it has the textarea popup for me to paste in my certificate.

I've got my domain certificate concatenated with my intermediary certificate, but there's a checkbox beneath the textarea that says "Automatically Add Intermediate Certificates"?

My bundle looks like this:

-----BEGIN CERTIFICATE-----
MY_DOMAIN_CERT_CODE
-----END CERTIFICATE-----
-----BEGIN CERTIFICATE-----
INTERMEDIATE_CERT_CODE
-----END CERTIFICATE-----

So, there's two ways to interpret this:

1. Check this box, and we'll locate your intermediary certificates for you and make sure they're set properly. But make sure you do NOT paste any intermediary certificate below yours. Let us do that for you.
2. Check this box, and we'll make sure the intermediary certificate you've appended below your domain certificate is set properly. But make sure you've pasted your intermediary certificate below your domain certificate.

There's the confusion. I've got my bundle already, so should I uncheck this box (which is checked by default by the way)?

This is one of those UI things that's ambiguous and the Forge knowledge base doesn't elaborate either.

Thanks.