The problem you were having is caused by the class 'tooltip_parent' that is used throughout the demo to transform the next html element with a class of 'tooltip' into a popup element that is shown when the parent element is focused on.
So to remove the 'Example Users' popup from the demo login page, you would remove the entire span with the classes 'tooltip width_400' (As you say you did), but then also remove the 'tooltip_parent' class from input element with an id of 'identity'.
