Rated 5 out of 5 stars

UPDATE: It now works again with the newest version 0.14.2013082301! Thanks for the fix! Now 5 stars.
This addons is the only reason I still use Firefox, even though Chromium is quicker and more responsive. Chromium lacks vertical tabs.

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Last update broke the addon on both Win7 (32 Bit) and Arch Linux (64 Bit).The old one from here works:https://addons.mozilla.org/firefox/downloads/file/210628/tree_style_tab-0.14.2013052901-fx.xpi?src=version-history Thanks to Hiroth for providing the link.

This review is for a previous version of the add-on (0.14.2013082201.1-signed).