It is fully manual customizable. You can add up to 15 menu items with unlimited sub menus each. Every menu and sub menu item can link to a web page but not mandatory.
The basic idea is that each time you click on a menu item, to display the sub menu without having to change the current page.
First of all you have to create all buttons graphically.
Ideally create 3 icons per option. 1 for active button, 1 for inactive and 1 for mouse over – hover.
Each button filenames should be like this:
You can create your buttons on photoshop or easily online:
See Drop up demo: http://www.mi-ro.gr