Changing web browser in preferred applications is not applied

[Jarno Suni]

After I changed the browser setting to Firefox, Internet-button in panel still starts Chromium browser (by x-www-browser) and ubuntu-bug uses Chromium as well.

ProblemType: Bug
DistroRelease: Ubuntu 13.04
Package: libfm-gtk-bin 1.1.0-0ubuntu2
ProcVersionSignature: Ubuntu 3.8.0-30.44-generic 3.8.13.6
Uname: Linux 3.8.0-30-generic x86_64
ApportVersion: 2.9.2-0ubuntu8.3
Architecture: amd64
Config_pcmanfm_System_Lubuntu: Error: [Errno 2] No such file or directory: '/etc/xdg/pcmanfm/lubuntu.conf'
Date: Mon Sep 23 17:12:19 2013
EcryptfsInUse: Yes
InstallationDate: Installed on 2013-09-20 (3 days ago)
InstallationMedia: Lubuntu 13.04 "Raring Ringtail" - Release amd64 (20130423.1)
MarkForUpload: True
Pref_Config_Home_Lubuntu:

SourcePackage: libfm
Udisks_dump: Error: [Errno 2] No such file or directory: 'udisks'
UpgradeStatus: No upgrade log present (probably fresh install)