I've been bugged that I can't configure firefox--it won't let me control which applications are used to open which kinds of files. I do not want pdf files to be viewed inside the browser window. It makes me feel cramped.
While reading the fedora list today, Aaron Konstam, a name which seems familiar to me somehow, posted a great tip.
"But to do what you want got to: about:config
browser.download.hide_plugins_without_extensions to false
The in: Edit->Preferences->Content->Manage you can make firefox any
program you want to open pdf files."