Comment 22 for bug 794720

I have discovered that the cause of this behaviour is a file conflict betweentwo seperate defaults.list files. In Mint 17 XFCE my /usr/share/applications/defaults.list and /etc/gnome/defaults.list point to a different web browser. My /usr/share/applications/defaults.list has the entries "x-scheme-handler/http=opera-browser.desktop" and "x-scheme-handler/https=opera-browser.desktop" while /etc/gnome/defaults.list has the entries "x-scheme-handler/http=firefox.desktop" and "x-scheme-handler/https=firefox.desktop". I have Opera set as my preferred application, and that is the browser which opens when exo-open --launch WebBrowser %u is called in the terminal. The applications that open the firefox browser must be reading their instructions from /etc/gnome/defaults.list. When the x-scheme-handler is changed to be opera-browser these applications launch opera in stead of firefox.