As of now, whenever I click "Open with..." when downloading a file, a copy of that file saves to my desktop and never gets cleared. I'd like to set the temporary folder so I can manually clear it periodically, but the only file management option I seem to have is to set downloads to always save in a certain folder--which does not appear to include "temporary" files. How can I change the destination folder for temporary downloads? And why does Firefox download and save the files before opening them? I don't want to save every PDF I read online, yet this seems to be the default setting in order to open files.