Firefox Web Browser header obscures Close/Minimise/Maximise buttons

[John Page]

When I access a website that opens another window, the title 'Firefox Web Browser' is not completely removed when I go to the top line of the display with my mouse. The options 'File Edit View...' appear, but the word 'Firefox' remains and obscures the window close/maximise/minimise buttons, making it impossible to close Firefox (although a workaround is to right click on the Firefox launcher and select Quit). The same thing occurs when I have several tabs open (as I do at the moment completing this report). I believe that this is a new 'feature' of 14.04 LTS - I did not observe this problem in 13.10.

I'm running Ubuntu 14.04 LTS, and here's the apt-cache policy output:

firefox:
  Installed: 28.0+build2-0ubuntu2
  Candidate: 28.0+build2-0ubuntu2
  Version table:
 *** 28.0+build2-0ubuntu2 0
        500 http://archive.ubuntu.com/ubuntu/ trusty/main amd64 Packages
        100 /var/lib/dpkg/status

ProblemType: Bug
DistroRelease: Ubuntu 14.04
Package: firefox 28.0+build2-0ubuntu2
ProcVersionSignature: Ubuntu 3.13.0-24.46-generic 3.13.9
Uname: Linux 3.13.0-24-generic x86_64
AddonCompatCheckDisabled: False
ApportVersion: 2.14.1-0ubuntu3
Architecture: amd64
AudioDevicesInUse:
 USER PID ACCESS COMMAND
 /dev/snd/controlC1: john 1974 F.... pulseaudio
 /dev/snd/controlC0: john 1974 F.... pulseaudio
BuildID: 20140410211200
Channel: Unavailable
CurrentDesktop: Unity
Date: Wed Apr 23 19:07:04 2014
ExecutablePath: /usr/lib/firefox/firefox
Extensions: extensions.sqlite corrupt or missing
ForcedLayersAccel: False
IfupdownConfig:
 # interfaces(5) file used by ifup(8) and ifdown(8)
 auto lo
 iface lo inet loopback
IncompatibleExtensions: Unavailable (corrupt or non-existant compatibility.ini or extensions.sqlite)
InstallationDate: Installed on 2014-04-19 (4 days ago)
InstallationMedia: Ubuntu 13.10 "Saucy Salamander" - Release amd64 (20131016.1)
IpRoute:
 default via 192.168.1.1 dev eth0 proto static
 192.168.1.0/24 dev eth0 proto kernel scope link src 192.168.1.66 metric 1
IwConfig:
 eth0 no wireless extensions.

 lo no wireless extensions.
Locales: extensions.sqlite corrupt or missing
PrefSources: prefs.js
Profiles: Profile0 (Default) - LastVersion=28.0/20140410211200 (In use)
RelatedPackageVersions:
 rhythmbox-mozilla 3.0.2-0ubuntu1
 totem-mozilla 3.10.1-1ubuntu4
RfKill:

RunningIncompatibleAddons: False
SourcePackage: firefox
Themes: extensions.sqlite corrupt or missing
UpgradeStatus: Upgraded to trusty on 2014-04-21 (1 days ago)
dmi.bios.date: 07/23/2010
dmi.bios.vendor: American Megatrends Inc.
dmi.bios.version: 2105
dmi.board.asset.tag: To Be Filled By O.E.M.
dmi.board.name: M4A785TD-V EVO
dmi.board.vendor: ASUSTeK Computer INC.
dmi.board.version: Rev X.0x
dmi.chassis.asset.tag: Asset-1234567890
dmi.chassis.type: 3
dmi.chassis.vendor: Chassis Manufacture
dmi.chassis.version: Chassis Version
dmi.modalias: dmi:bvnAmericanMegatrendsInc.:bvr2105:bd07/23/2010:svnSystemmanufacturer:pnSystemProductName:pvrSystemVersion:rvnASUSTeKComputerINC.:rnM4A785TD-VEVO:rvrRevX.0x:cvnChassisManufacture:ct3:cvrChassisVersion:
dmi.product.name: System Product Name
dmi.product.version: System Version
dmi.sys.vendor: System manufacturer