Delete button backend (Pro-sites)

Hello guys,

I am trying to delete this button:

I think I found the string in the file gateway.php, but when I delete it, it's still there.
Here is the string that I found:

It make no sense to me. It is in perfect order regardin to the other stuff on the page, in the file. Do I have to delete more than just the string I marked on the picture?

Thanks

Nicolaj