There's at least three posts addressing the Spit At Cursor button (one even includes a picture with an arrow pointing to it). And in addition to already answering the question, there's also every conceivable way of splitting (at cursor or at marker) being pointed out as well (including keyboard shortcuts). I even included what the text of the tooltip of the button he was looking for should be when a mouse pointer hovers over it.
You have an odd definition of unhelpful.
