Can you try running "sudo update-alternatives --config x-www-browser" and than see if it keeps it as default without asking you.
** Changed in: firefox (Ubuntu)
Status: Unconfirmed => Needs Info
--
Firefox cant cope with default browser setting
https://launchpad.net/bugs/78204
--
ubuntu-bugs mailing list
[email protected]
https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
