deleting first ‘extra’ button

hi, been using this on a site for a while, really useful. client has just remarked that they are unable to REMOVE the first button. i’m not sure if this was always the case? they have some products they don’t want any extra URL buttons on, but there is always one BLANK button, there is a DELETE next to it, but it keeps reappearing after trying to delete. is this a known thing, can it be fixed?
many thanks!