I have now forwarded this bug to upstream: https://bugzilla.mozilla.org/show_bug.cgi?id=1143402
** Bug watch added: Mozilla Bugzilla #1143402 https://bugzilla.mozilla.org/show_bug.cgi?id=1143402 -- You received this bug notification because you are a member of Desktop Packages, which is subscribed to firefox in Ubuntu. https://bugs.launchpad.net/bugs/1407174 Title: Firefox claims to be not the default browser while x-www-browser opens it Status in firefox package in Ubuntu: New Bug description: I'm using Ubuntu 15.04 dev with firefox 34.0+build2-0ubuntu2 and if I'm going to the menu bar -> Edit -> Preferences -> General there stands "Firefox is not your default browser". But if I'm executing x -www-browser in a terminal Firefox does successfully start. To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/firefox/+bug/1407174/+subscriptions -- Mailing list: https://launchpad.net/~desktop-packages Post to : desktop-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~desktop-packages More help : https://help.launchpad.net/ListHelp