Dear Maintainer, I can replicate this bug on a 100% wheezy + wheezy-backports machine with most recent updates for Iceweasel 30 (30.0.a2 03-21-2014). Regular Firefox Aurora of the same build did not have the issue.
Issues are as follows: -Previously-Installed Restartless Add-Ons or Ones Installed After Update Appear Installed but lose toolbar icons and all functionality. Anything installed new loses persistence. -Sync is broken -Customize is broken and reads a blank white screen -Certain things like the dev tools toolbar icon menu lose 75% of the native dev tools, which sometimes aren't accessible in the regular methods either. Package: iceweasel Version: 30.0~a2+20140321004003-1~bpo70+1 Severity: important -- Package-specific info: -- Extensions information Name: 000 userstyle Status: enabled Name: Adblock Plus Location: /usr/share/mozilla/extensions/{ec8030f7-c20a-464f-9b0e-13a3a9e97384}/{d10d0bf8-f5b5-c8b4-a8b2-2b9879e08c5d} Package: xul-ext-adblock-plus Status: enabled Name: Cleanest Addon Manager Location: ${PROFILE_EXTENSIONS}/c...@sdrocking.com.xpi Status: enabled Name: ColorZilla Location: ${PROFILE_EXTENSIONS}/{6AC85730-7D0F-4de0-B3FA-21142DD85326} Status: enabled Name: Cookies Manager+ Location: ${PROFILE_EXTENSIONS}/{bb6bc1bb-f824-4702-90cd-35e2fb24f25d} Status: enabled Name: Default theme Location: /usr/lib/iceweasel/browser/extensions/{972ce4c6-7e08-4474-a285-3208198ce6fd} Package: iceweasel Status: user-disabled Name: DuckDuckGo Plus Location: ${PROFILE_EXTENSIONS}/jid1-zadieub7xoz...@jetpack.xpi Status: enabled Name: Facebook userstyle Status: enabled Name: Flagfox Location: ${PROFILE_EXTENSIONS}/{1018e4d6-728f-4b20-ad56-37578a4de76b}.xpi Status: enabled Name: Ghostery Location: ${PROFILE_EXTENSIONS}/fire...@ghostery.com.xpi Status: enabled Name: Google Analytics Opt-out Browser Add-on Location: ${PROFILE_EXTENSIONS}/{6d96bb5e-1175-4ebf-8ab5-5f56f1c79f65}.xpi Status: enabled Name: Green Floral theme Status: user-disabled Name: HTTPS-Everywhere Location: ${PROFILE_EXTENSIONS}/https-everywh...@eff.org Status: enabled Name: HoofSounds Location: ${PROFILE_EXTENSIONS}/hoofsou...@hoofsounds.little.my.xpi Status: enabled Name: NoScript Location: ${PROFILE_EXTENSIONS}/{73a6fe31-595d-460b-a920-fcc0f8843232}.xpi Status: enabled Name: Personas Plus Location: ${PROFILE_EXTENSIONS}/perso...@christopher.beard.xpi Status: enabled Name: Ponyhoof Location: ${PROFILE_EXTENSIONS}/ponyh...@ponyhoof.little.my.xpi Status: enabled Name: Ponyhoof Location: ${PROFILE_EXTENSIONS}/ponyh...@hoof.little.my.xpi Status: enabled Name: Private Tab Location: ${PROFILE_EXTENSIONS}/private...@infocatcher.xpi Status: enabled Name: Scriptify Location: ${PROFILE_EXTENSIONS}/script...@dactyl.googlecode.com.xpi Status: enabled Name: Stylish Location: ${PROFILE_EXTENSIONS}/{46551EC9-40F0-4e47-8E18-8E5CF550CFB8}.xpi Status: enabled Name: Summerwood theme Status: enabled Name: Tab Mix Plus Location: ${PROFILE_EXTENSIONS}/{dc572301-7619-498c-a57d-39143191b318}.xpi Status: enabled Name: The Snowy Mountains Theme theme Status: user-disabled Name: Tumblr Cleanup userstyle Status: enabled Name: Web Developer Location: ${PROFILE_EXTENSIONS}/{c45c406e-ab73-11d8-be73-000a95be3b12}.xpi Status: enabled Name: XKit Location: ${PROFILE_EXTENSIONS}/x...@studioxenix.com.xpi Status: enabled -- Plugins information Name: Gnome Shell Integration Location: /usr/lib/mozilla/plugins/libgnome-shell-browser-plugin.so Package: gnome-shell Status: enabled Name: Java(TM) Plug-in 10.51.2 (10.51.2) Location: /usr/lib/jvm/jdk1.7.0_51/jre/lib/amd64/libnpjp2.so Status: enabled Name: Shockwave Flash (11.2.202.341) Location: /usr/lib/flashplugin-nonfree/libflashplayer.so Status: enabled Name: iTunes Application Detector Location: /usr/lib/mozilla/plugins/librhythmbox-itms-detection-plugin.so Package: rhythmbox-plugins Status: disabled -- Addons package information ii gnome-shell 3.4.2-7+deb7 amd64 graphical shell for the GNOME des ii iceweasel 30.0~a2+2014 amd64 Web browser based on Firefox ii rhythmbox-plug 2.97-2.1 amd64 plugins for rhythmbox music playe ii xul-ext-adbloc 2.1-1+deb7u1 all Advertisement blocking extension -- System Information: Debian Release: 7.4 APT prefers stable-updates APT policy: (500, 'stable-updates'), (500, 'stable'), (500, 'oldstable') Architecture: amd64 (x86_64) Foreign Architectures: i386 Kernel: Linux 3.2.0-4-amd64 (SMP w/4 CPU cores) Locale: LANG=en_US.UTF-8, LC_CTYPE=en_US.UTF-8 (charmap=UTF-8) Shell: /bin/sh linked to /bin/dash Versions of packages iceweasel depends on: ii debianutils 4.3.2 ii fontconfig 2.9.0-7.1 ii libc6 2.13-38+deb7u1 ii libgdk-pixbuf2.0-0 2.26.1-1 ii libglib2.0-0 2.33.12+really2.32.4-5 ii libgtk2.0-0 2.24.10-2 ii libsqlite3-0 3.7.13-1+deb7u1 ii libstdc++6 4.7.2-5 ii procps 1:3.3.3-3 ii xulrunner-30 30.0~a2+20140321004003-1~bpo70+1 iceweasel recommends no packages. Versions of packages iceweasel suggests: pn fonts-mathjax <none> pn fonts-oflb-asana-math <none> ii fonts-stix [otf-stix] 1.1.0-1 ii libgssapi-krb5-2 1.10.1+dfsg-5+deb7u1 pn mozplugger <none> Versions of packages xulrunner-30 depends on: ii libasound2 1.0.25-4 ii libatk1.0-0 2.4.0-2 ii libbz2-1.0 1.0.6-4 ii libc6 2.13-38+deb7u1 ii libcairo2 1.12.2-3 ii libdbus-1-3 1.6.8-1+deb7u1 ii libdbus-glib-1-2 0.100.2-1 ii libevent-2.0-5 2.0.19-stable-3 ii libffi5 3.0.10-3 ii libfontconfig1 2.9.0-7.1 ii libfreetype6 2.4.9-1.1 ii libgcc1 1:4.7.2-5 ii libgdk-pixbuf2.0-0 2.26.1-1 ii libglib2.0-0 2.33.12+really2.32.4-5 ii libgtk2.0-0 2.24.10-2 ii libhunspell-1.3-0 1.3.2-4 ii libpango1.0-0 1.30.0-1 ii libstartup-notification0 0.12-1 ii libstdc++6 4.7.2-5 ii libx11-6 2:1.5.0-1+deb7u1 ii libxext6 2:1.3.1-2+deb7u1 ii libxrender1 1:0.9.7-1+deb7u1 ii libxt6 1:1.1.3-1+deb7u1 ii zlib1g 1:1.2.7.dfsg-13 Versions of packages xulrunner-30 suggests: ii libcanberra0 0.28-6 ii libgnomeui-0 2.24.5-2 -- no debconf information