This question is an exact duplicate of:
The achievements drop-down menu in the new top bar shows me when a question/answer earns me reputation and how much, and that's great, but I don't know what caused that to happen. I'd like to know why I received reputation: was it an upvote? An accepted answer? An accepted edit? If I have the list of reputation values in my head I can figure it out, but it would help me to see it somewhere in the drop-down, even as title text on hover.
It sounds like the items in the menu can roll up multiple events, and that's why it doesn't show the event there. How about adding a link to my reputation tab to the menu so I can quickly get to a breakdown?