"load links into a new tab" doesn't work

As it is well noted in the "Préférences" of the menu :
Load web browser links into a : new tab
Load external links into a : new tab

The web browser links always open into the current tab !
(it's ok with the external links which well open into a new tab)

ProblemType: Bug
DistroRelease: Ubuntu 11.10
Package: firefox 11.0+build1-0ubuntu0.11.10.1
ProcVersionSignature: Ubuntu 3.0.0-16.29-genusername 3.0.20
Uname: Linux 3.0.0-16-generic i686
NonfreeKernelModules: nvidia
AddonCompatCheckDisabled: False
AlsaVersion: Advanced Linux Sound Architecture Driver Version 1.0.24.
ApportVersion: 1.23-0ubuntu4
Architecture: i386
AudioDevicesInUse:
 USER PID ACCESS COMMAND
 /dev/snd/controlC0: eric 1574 F.... pulseaudio
BuildID: 20120310010446
CRDA: Error: [Errno 2] Aucun fichier ou dossier de ce type
Card0.Amixer.info:
 Card hw:0 'Intel'/'HDA Intel at 0xfdff4000 irq 44'
   Mixer name : 'Realtek ALC888'
   Components : 'HDA:10ec0888,1028020d,00100001'
   Controls : 40
   Simple ctrls : 22
Channel: release
Date: Fri Mar 16 18:29:11 2012
ForcedLayersAccel: False
IfupdownConfig:
 auto lo
 iface lo inet loopback
InstallationMedia: Ubuntu 10.10 "Maverick Meerkat" - Release i386 (20101007)
IpRoute:
 default via 88.185.79.254 dev eth0 proto static
 88.185.79.0/24 dev eth0 proto kernel scope link src 88.185.79.42 metric 1
 169.254.0.0/16 dev eth0 scope link metric 1000
Profiles: Profile0 (Default) - LastVersion=11.0/20120310010446 (Running)
RfKill:
 0: phy0: Wireless LAN
  Soft blocked: no
  Hard blocked: no
RunningIncompatibleAddons: False
SourcePackage: firefox
UpgradeStatus: Upgraded to oneiric on 2011-10-15 (153 days ago)
dmi.bios.date: 07/12/2007
dmi.bios.vendor: Dell Inc.
dmi.bios.version: 1.0.3
dmi.board.name: 0RY007
dmi.board.vendor: Dell Inc.
dmi.board.version: ���
dmi.chassis.type: 3
dmi.chassis.vendor: Dell Inc.
dmi.chassis.version: OEM
dmi.modalias: dmi:bvnDellInc.:bvr1.0.3:bd07/12/2007:svnDellInc.:pnInspiron530:pvr:rvnDellInc.:rn0RY007:rvr:cvnDellInc.:ct3:cvrOEM:
dmi.product.name: Inspiron 530
dmi.sys.vendor: Dell Inc.