overflow-x:visible css property doesnt work -

I have a vertical menu in my web page, I have given a specific height to the container div in the menu. I only tried to scroll vertical overflow but not horizontal scroll, but when I hover over the menu item, it shows horizontal scroll instead of showing submenu.

My CSS is below

  .navdiv {overflow-y: scroll; Height: 380px; Overflow-x: visible; }  

I tried all the variations of the overflow -x but have no use