I wish it is solved, this problem is puzzling.
When you click the Next / Prev buttons, the items slides, at this moment when they move (left / right) they will appear outside the box. Until the movement complete.
Apparently all the available sliders work the same, its not only the hidden overflow attribute a problem, there is some translate3d on many divs as part of the problem.
Do you think we can move the tooltip outside the slider ?