Drop Down Menu Direction – Vantage Theme

It should be possible to change the direction of the Drop Down Menus as detailed in this article:

Changing Drop Down Menu Direction

By default drop down menus appear to the right of their parent menu item. Right alignment can be an issue for menu items close to the end of the screen, causing items to disappear off the edge of the screen. To change the direction of a drop down menu, follow these steps:

Go to AppearanceMenus and click Screen Options top right. Under Show advanced menu properties enable CSS classes.

Locate a drop down parent menu item and click the down arrow next to the menu item name.

Go to the CSS Classes (optional) field and enter the following:

left

Sub-menu items of the parent item with the CSS class will now display to the left instead of right.

I am using the Vantage Theme and cannot get this to work!

Any suggestions?

Thank you