If you want to use different program for all file types it could assosate with currently you have to go through every file type in FileAssosiations and manually adjust assosiation for each of them.
Steps to Reproduce:
1. SystemSettings -> FileAssosiations
2. No option to change file assosiations for program
I've made a simple mockup(if you can even call it this way) http://s18.postimg.org/k3p3z89ah/File_Assosiatio_Proposal.jpg to shwo what i mean.
*** This bug has been marked as a duplicate of bug 254560 ***
*** This bug has been marked as a duplicate of bug 61582 ***