vertical drop-down menu from bottom but not from the side ?

Hi

I am using the vertical drop down menu, I have try all the style, all the drop down child menu are come out from the right side of the parent menu.

I want all the child menu are come out just from the bottom of the parent menu which is the normal way of most of the website.

How can I do this ? Do I need to change the css or I don't see any setting for this ?? Thanks