Dynamic menu

does anyone know how to create a menu that when your cursor move onto any item, an object will follows smoothly to the item, but when your cursor are not on any item, it just stay where it is last placed, {{{{and it will also remember what content link to the item you are viewing and thus highlight the item and disable the associated button.}}}}(optional)
hopefully this is not confusing
any reference to other related article or just a jargon to call this kind of menu would be good, I have seen it somewhere, but when I want that effect, just have no clue about how to search for them.
thank in advance:pleased: