Slider overrides menu items

Hello,
I’am using Smoth Slider 2.5.1 and Twenty Fourteen 1.1 theme.
When I hover over the menu item the submenu items can’t be read since they get overridden by the slider.

I have see the topic: “Slider overrides menu items” but the solution proposed doesn’t work for me.

My site is: http://wmg.staitranquillo.it/ (Menu Item : “Corsi Web Marketing” It’s the second menu item from the left with which I’m having this trouble. )

Can you help me?

Thanks

roberto

https://wordpress.org/plugins/smooth-slider/