In all of my portals, I always get an extra portal row/record at the end. I do allow records to be created via the relationship, but is there anyway to disable this?

untick, "allow creation of related records in this table via relationship" when editing the relationship.

I think he meant, can you disable the extra row, while still allowing creation of related records. No, you can't.

I'm guessing you're putting a button on the portal row that you don't want to show up? That can be worked around by using a calculated container field for the graphic.

Or, you can turn off "allow creation" and create related records using a script instead.