Mozilla/5.0 (X11; U; SunOS i86pc; en-US; rv:1.9) Gecko/2008052423 Firefox/3.0 Steps to Perform: 1. Start a download 2. Try to quit from File | Quit Expected Results: You get a "A download is in progress, are you sure you want to quit?" dialog Actual Results: No warning dialog appear as above. If there are more than one tab, we can get this kind of warning "Do you want Firefox to save your tabs and windows for the next time it starts?"
note that Firefox will stop the download and resume it when it's restarted
This is intentional, see Bug 414161.
verified, although this may be a dupe, I cannot find it.