Re: Firefox download tabs
While I use SeaMonkey rather than Firefox, I’ve just watched a quick video from their blogs to see how the download manager works differently between the 2.
It sounds like the arrow is the Download Manager icon, and the window or panel which opens when you click it is called the Download Panel. That panel lists the downloads you’ve pulled or are pulling, the newest at the top of the list. Right-clicking on an entry gives you options to pause, etc. A folder icon next to an entry is a link to open Windows Explorer to show the actual file downloaded.
If there’s a setting in the preferences for Firefox to change whether you see a panel or a new tab open to view the Manager’s list of downloads, that’s local to your login. As for duplicate entries, esp. without being able to able to duplicate the issue with commercial sites, or your own devs as well, would tend to point to something in your FF profile. Try clearing the browser’s cache and download lists, or even create a new profile with no add-ons and see whether the problem persists. But since you seem to be the only one with the issue, it’s almost certainly in your profile.