My question is related to Remove link to something that is not a folder in the Finder sidebar, but my problem is fundamentally different.
I still have file links appearing in my folder sidebar. But I know how to remove those links, I just right-click and choose the option Remove from the sidebar.
I actually have no idea how files end up appearing in there: I don't drag them, I don't do anything special. Actually, if I drag them, I get a nice Forbidden icon. So I don't get how they should even appear.
So why do they appear there and how can I prevent this from happening?
I have Mountain Lion 10.8.2.