fedex parcel number found click "track package" for information

Whenever I open my Gmail, there is a pop-up like information bar on the top of my explorer near the tool bar. it says: "FedEx parcel number found click 'track package' for information". This information bar disappear in several second, no where to click on.

I searched for any explanations on the Internet, but the only most likely one I could find is a package tracker plug-in.

I am sure I haven't installed such plug-in as package tracker, have any idea on this?