Messaging Menu and Unity launcher does not display unread messages count from Thunderbird

[Alkalyzer]

I made a clean install of Oneiric (64bits edition) using all defaults options and now, when I receive new messages in Thunderbird, the letter from the Messaging Menu doesn't turn blue and I don't have any update of the message count in the Menu either.
This was working fine previously when I was running Natty. I use two e-mail accounts which both use the IMAP protocols.

The only three fields visible in the Messaging Menu, in the e-mail part, are : Mail, Compose New Message and Contacts which work as they should be.
Whether I enable the Messaging Menu and Unity Integration Add-on in Thunderbird or not, the problem is still here.
In the other hand, the on-screen notifications work perfectly.

I also discovered that the Thunderbird Unity launcher might also display unread messages count. If this is the case, it not working either.

While looking for such an already described bug in launchpad, I found bug #850229 being similar but not identical. I think the bug I report here might be different because i) I never have any update on the Unity launcher and ii) I don't have any update either of the unread messages count in the messaging menu. I think the case of bug #850229 was related to a wrong value of unread messages and not to the total absence of this value.
In the discussion about bug #850299, comment #4 seems to correspond to the bug I report here.

ProblemType: Bug
DistroRelease: Ubuntu 11.10
Package: thunderbird 7.0.1+build1+nobinonly-0ubuntu1
ProcVersionSignature: Ubuntu 3.0.0-12.20-generic 3.0.4
Uname: Linux 3.0.0-12-generic x86_64
NonfreeKernelModules: nvidia
AddonCompatCheckDisabled: False
AlsaVersion: Advanced Linux Sound Architecture Driver Version 1.0.24.
ApportVersion: 1.23-0ubuntu3
Architecture: amd64
AudioDevicesInUse:
 USER PID ACCESS COMMAND
 /dev/snd/controlC0: lionel 1915 F.... pulseaudio
 /dev/snd/pcmC0D0p: lionel 1915 F...m pulseaudio
BuildID: 20110929183320
CRDA: Error: [Errno 2] No such file or directory
Card0.Amixer.info:
 Card hw:0 'Intel'/'HDA Intel at 0xf0400000 irq 46'
   Mixer name : 'Nvidia MCP77/78 HDMI'
   Components : 'HDA:10ec0888,1025015e,00100202 HDA:14f12c06,1025015e,00100000 HDA:10de0006,10de0101,00100000'
   Controls : 29
   Simple ctrls : 16
Channel: release
Date: Sun Nov 6 20:45:43 2011
ExecutablePath: /usr/lib/thunderbird-7.0.1/thunderbird-bin
ForcedLayersAccel: False
IfupdownConfig:
 auto lo
 iface lo inet loopback
InstallationMedia: Ubuntu 11.10 "Oneiric Ocelot" - Release amd64 (20111012)
IpRoute:
 default dev tun0 proto static
 169.254.0.0/16 dev wlan0 scope link metric 1000
 192.168.1.0/24 dev wlan0 proto kernel scope link src 192.168.1.4 metric 2
 193.10.16.0/22 dev tun0 proto kernel scope link src 193.10.16.103
 193.10.16.3 via 192.168.1.1 dev wlan0 proto static
ProcEnviron:
 PATH=(custom, no user)
 LANG=en_US.UTF-8
 SHELL=/bin/bash
Profiles: Profile0 (Default) - LastVersion=7.0.1/20110929183320 (Running)
RunningIncompatibleAddons: False
SourcePackage: thunderbird
UpgradeStatus: No upgrade log present (probably fresh install)
dmi.bios.date: 09/12/2008
dmi.bios.vendor: Acer
dmi.bios.version: v0.3121
dmi.board.name: Makalu
dmi.board.vendor: Acer, Inc.
dmi.board.version: Not Applicable
dmi.chassis.type: 1
dmi.chassis.vendor: Acer, Inc.
dmi.chassis.version: N/A
dmi.modalias: dmi:bvnAcer:bvrv0.3121:bd09/12/2008:svnAcer,inc.:pnAspire6930G:pvrNotApplicable:rvnAcer,Inc.:rnMakalu:rvrNotApplicable:cvnAcer,Inc.:ct1:cvrN/A:
dmi.product.name: Aspire 6930G
dmi.product.version: Not Applicable
dmi.sys.vendor: Acer, inc.

[Natim (site-remy)]

What you can do :

Open : "Tools -> Options -> Advanced -> General -> Config Editor (button)"

Search for `extensions.messagingmenu.inboxOnly` set it to true and that's it.