Well, this question might have been asked (and answered) before, but I haven't found any good (and current) information besides this 3-year old post, that explains a way to allow Firefox to warn before closing if a download is being made.
To sum up: Does closing Firefox completely (i.e. closing all windows, no
firefox.exe process remaining) stop or cancel an active download? And an upload (such as one made to Dropbox)?
I'm not specific about the OS used as I am assuming the behavior is identical to all OS Firefox has been ported.
If so, and besides having a download manager (like DownThemAll) or the good old download UI (accessible through
about:config > browser.download.useToolkitUI = True, that is the same as having an active Firefox process) is there a way to download / upload without worrying I might accidentally close Firefox?