Strange tab drag out behaviour

[Bob Bib]

When I drag the some tab out of the main window to move it to a separate window, the new window doesn't have a tab "handle", but only a "+" tab button; look at 'firefox_bug_screenshot.png'.
BTW, "Move to New Window" context menu option works correctly.

Occurred in Firefox 10 on Ubuntu 11.10, then in Firefox 11 on current development Ubuntu 12.04. Clean installs are not affected.

ProblemType: Bug
DistroRelease: Ubuntu 12.04
Package: firefox 11.0+build1-0ubuntu1
ProcVersionSignature: Ubuntu 3.2.0-18.29-generic 3.2.9
Uname: Linux 3.2.0-18-generic x86_64
AddonCompatCheckDisabled: False
AlsaVersion: Advanced Linux Sound Architecture Driver Version 1.0.24.
ApportVersion: 1.94.1-0ubuntu2
Architecture: amd64
ArecordDevices:
 **** List of CAPTURE Hardware Devices ****
 card 0: Intel [HDA Intel], device 0: ALC269 Analog [ALC269 Analog]
   Subdevices: 1/1
   Subdevice #0: subdevice #0
AudioDevicesInUse:
 USER PID ACCESS COMMAND
 /dev/snd/controlC0: mrbb 2067 F.... pulseaudio
BuildID: 20120313141247
Card0.Amixer.info:
 Card hw:0 'Intel'/'HDA Intel at 0xe4500000 irq 45'
   Mixer name : 'Intel Cantiga HDMI'
   Components : 'HDA:10ec0269,10250229,00100004 HDA:80862802,80860101,00100000'
   Controls : 29
   Simple ctrls : 13
Channel: release
Date: Thu Mar 15 19:21:52 2012
ExecutablePath: /usr/lib/firefox/firefox
ForcedLayersAccel: False
IfupdownConfig:
 auto lo
 iface lo inet loopback
IncompatibleExtensions:
 FlashGot - ID={19503e42-ca3c-4c27-b1e2-9cdb2170ee34}, Version=1.4, minVersion=1.9a3, maxVersion=1.9.*, Location=app-profile, Type=extension, Active=Yes
 FilesTube Crawler - <email address hidden>, Version=0.4, minVersion=1.5, maxVersion=4.*, Location=app-profile, Type=extension, Active=Yes
 NoScript - ID={73a6fe31-595d-460b-a920-fcc0f8843232}, Version=2.3.4, minVersion=1.9a2, maxVersion=1.9.6, Location=app-profile, Type=extension, Active=Yes
IpRoute:
 default via 10.1.1.1 dev wlan0 proto static
 10.1.1.0/24 dev wlan0 proto kernel scope link src 10.1.1.3 metric 2
 169.254.0.0/16 dev wlan0 scope link metric 1000
Profiles: Profile0 (Default) - LastVersion=11.0/20120313141247 (Running)
RunningIncompatibleAddons: True
SourcePackage: firefox
UpgradeStatus: Upgraded to precise on 2012-03-07 (7 days ago)
dmi.bios.date: 08/10/2010
dmi.bios.vendor: Acer
dmi.bios.version: V1.28
dmi.board.asset.tag: Base Board Asset Tag
dmi.board.name: Aspire 3810T
dmi.board.vendor: Acer
dmi.board.version: PSMBOU-1234567
dmi.chassis.type: 10
dmi.chassis.vendor: Acer
dmi.chassis.version: None
dmi.modalias: dmi:bvnAcer:bvrV1.28:bd08/10/2010:svnAcer:pnAspire3810T:pvrV1.28:rvnAcer:rnAspire3810T:rvrPSMBOU-1234567:cvnAcer:ct10:cvrNone:
dmi.product.name: Aspire 3810T
dmi.product.version: V1.28
dmi.sys.vendor: Acer

[Bob Bib (bobbib)]

Screenshot uploaded to Launchpad.

[Bob Bib (bobbib)]

Still affected: firefox 12.0+build1-0ubuntu0.12.04.1
Maybe, it's a problem with a some of the plugins.

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.

[Bob Bib (bobbib)]

Using the current user profile with an "older" ESR Firefox version (10.0) resulted in the same buggy functionality;
possibly, the bug is caused by extensions (perhaps, it needs a one-by-one extensions test);
the problem's gone after cleaning the files where extensions info is stored: http://kb.mozillazine.org/Profile_folder_-_Firefox

[Paul White (paulw2u)]

Problem resolved by reporter in comment #5 so closing.