Indicating the item has sub menu in collapsed navigation
Problem
When the navigation is collapsed, there are no hints to tell users which item has sub menu while mousing over it. For me, I would think it has a bug when the point is over the item which doesn't have sub menu. They have the same looking, so users would probably expect they all have the same interaction.
Proposal
Having a small icon on the right-bottom corner to indicate it has a sub menu.
