Nope. There's no way to disable it. Maybe something to add to the next release, but actually, I don't see the point. It's never collapsed by default, so the display doesn't change much between. Just don't click the minus buttons.
I would want to as it is adding visual noise - and it is not even working properly, you can end () on another line and it has phantom arms stretching below the actual last ) , hence the visual noise.