ASPxMenu - How to show a sub menu with a full page width

While our team is still working on this functionality in the context of the ASPxMenu - Provide an option to show a sub menu with a full page width  thread, you can accomplish this task in the following manner: 

[CSS]
.subMenu{width:100%;box-sizing:border-box;}.subMenu>div{margin:0auto;}

2) Handle the client-side PopUp event to adjust a sub menu:

[JScript]
function OnPopup(menu, e){var el = menu.GetMenuElement(e.item.indexPath);
            el.style.left = 0;
            el.style.right = 0;
            el.style.width = '100%';} 

The example below demonstrates this approach in action.