Wrong version of Firefox

[John Coppens]

Hi all,

After installing the new version of Firefox (35), XFCE still starts the 
previous version (27).

In /usr/lib64, I have a symlink 'firefox' which points to the directory
of the Firefox in use (so, at the moment, to firefox-35.0.1).

If I start FF from the menu, I get version 35, as expected (the
launcher points to 'firefox'. But when I reboot, I get version 27 (from
the previous session). This causes a lot of headaches, as version 27
disables some add-ons from v35, which I then have to re-enable.

The mozilla-firefox.desktop file points to 'firefox', and starts the
correct version. Executing 'firefox' in a terminal finds the correct
version too.

How's that? Is the session somehow pointing to the absolute location?
Where is that information saved? Maybe 'Preferred applications' is
pointing to the wrong one?

John