It's easy to indicate an item is a dropdown when the item has a rectanglar shape. For example, . But when the item has a circular shape
, what's the best position to place the indicator?
I would say there are three options:
After some explanations, what I understand is that you want to use it for user menu. I think it is quite common to have user menu, and I'm really not sure if it needs a special dropdown indicator. Look at the quick wireframe below. Once you communicate visually it is user related section, users will click it revealing menu (or even better: discover it after hovering on the icon).
I'd say that there is something fishy with this situation. Is it really a "dropdown" and not a contextual menu you're going for?
Although they usually are very similar, the functionality differ in a couple of subtle ways.
If the circle is representing some kind of object, how would you indicate - if at all - that the object is clickable and subject to a contextual menu?