"#" or even "" or even nonexistence of an href attribute of an element still in most browsers makes the element clickable. So previous response will not work 100% It depends on your theme menu and your needs/abilities how to handle the code. There are 2 basic options if you do not want to change whole menu code:
- replace element on apropriate places (on top + on parent links) with something like or but this can lead to necessity of major css editing.
or
- on those places include in element this attribude:
onclick="return false;"
It will work in all major browsers well. You can add styles to make an arrow cursor, disable underlines and so on.