Dropdown menu showing horizontal instead of vertical

Hi,
we have configured our main menu subvoices, but they are curiosusly showing horizontally alligned, instead of vertically as in the demo.
http://editionsafrique.com/ Main Menu > Editions
Any idea for how to make it come back to vertical dropdown?
thank you a lot

If you want to show menu items vertical you can't use columns settings, please disable 5 column layout in parent element and group separation for every item. Probably you use quickstart package and edit our default multicolumn menu - my advise is to remove all menu items and just add one column submenu.

and just add one column submenu.

Thank you for your asnwer. Sorry for our ignorance but, how can we "add one column submenu". Appearently we can't find where to give this option.

Thank you again.

Menu layout is defined in every menu item settings, you should find there GavickPro advanced menu settings. Every parent element for columns have set how many columns you want to display and there you need to change value to 1 (right now it is probably 5).