I'm seeing this problem with all GTK applications, not just Firefox. They work fine after first booting up, but after logging out and then back in they all show black text on black backgrounds and don't revert to normal without rebooting.
Could be releated to this bug: https://bugs.launchpad.net/ubuntu/+source /lubuntu-artwork/+bug/938472 -- You received this bug notification because you are a member of Desktop Packages, which is subscribed to firefox in Ubuntu. https://bugs.launchpad.net/bugs/951725 Title: Black Background Status in “firefox” package in Ubuntu: Confirmed Bug description: Using FF 11, when I logoff and then log back on again, the FF background is black. ProblemType: Bug DistroRelease: Ubuntu 12.04 Package: firefox 11.0~b7+build1-0ubuntu1 ProcVersionSignature: Ubuntu 3.2.0-18.28-generic 3.2.9 Uname: Linux 3.2.0-18-generic i686 NonfreeKernelModules: nvidia AddonCompatCheckDisabled: False AlsaVersion: Advanced Linux Sound Architecture Driver Version 1.0.24. ApportVersion: 1.94.1-0ubuntu2 Architecture: i386 AudioDevicesInUse: USER PID ACCESS COMMAND /dev/snd/controlC0: phil 1822 F.... pulseaudio BuildID: 20120309112843 Card0.Amixer.info: Card hw:0 'ICH7'/'Intel ICH7 with AD1981B at irq 23' Mixer name : 'Analog Devices AD1981B' Components : 'AC97a:41445374' Controls : 28 Simple ctrls : 20 Channel: beta CurrentDmesg: [ 1017.764387] soffice.bin[2826]: segfault at 629ce78 ip 0398e0ab sp bfb9e910 error 4 in libQtCore.so.4.8.0[3812000+2d4000] Date: Sat Mar 10 11:41:05 2012 ForcedLayersAccel: False IfupdownConfig: auto lo iface lo inet loopback IncompatibleExtensions: Test Pilot - [email protected], Version=1.2, minVersion=3.5, maxVersion=10.0a1, Location=app-profile, Type=extension, Active=Yes InstallationMedia: Kubuntu 11.10 "Oneiric Ocelot" - Release i386 (20111012) IpRoute: default via 192.168.1.1 dev eth0 proto static 169.254.0.0/16 dev eth0 scope link metric 1000 192.168.1.0/24 dev eth0 proto kernel scope link src 192.168.1.109 metric 1 Plugins: Shockwave Flash - Lib=libflashplayer.so, Location=/usr/lib/flashplugin-installer Skype Buttons for Kopete - Lib=skypebuttons.so, Location=/usr/lib/mozilla/plugins ProcEnviron: LANG=en_US.UTF-8 SHELL=/bin/bash Profiles: Profile0 (Default) - LastVersion=11.0/20120309112843 (Running) RfKill: 0: phy0: Wireless LAN Soft blocked: no Hard blocked: no RunningIncompatibleAddons: True SourcePackage: firefox UpgradeStatus: Upgraded to precise on 2012-03-10 (0 days ago) dmi.bios.date: 11/30/2006 dmi.bios.vendor: Dell Inc. dmi.bios.version: A11 dmi.board.name: 0HH807 dmi.board.vendor: Dell Inc. dmi.chassis.type: 6 dmi.chassis.vendor: Dell Inc. dmi.modalias: dmi:bvnDellInc.:bvrA11:bd11/30/2006:svnDellInc.:pnOptiPlexGX620:pvr:rvnDellInc.:rn0HH807:rvr:cvnDellInc.:ct6:cvr: dmi.product.name: OptiPlex GX620 dmi.sys.vendor: Dell Inc. To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/firefox/+bug/951725/+subscriptions -- Mailing list: https://launchpad.net/~desktop-packages Post to : [email protected] Unsubscribe : https://launchpad.net/~desktop-packages More help : https://help.launchpad.net/ListHelp

