http://board.jdownloader.org/showthread.php?t=48860
Addressed in that thread, the mod said there's no one else complaining about it, but well, no one can if you lock the thread;)
Basically its a UI issue, the delete "broom" button is duplicated on both tabs in a way that its very easy to accidentally have a problem. Sure you can say be more careful, but generally good UI design should be to take more load off the user and prevent any accidents right? Maybe for the main tab download tab the broom should be moved to a different area of the window so no accidents can happen? Just a suggestion.
Thanks.