Okay, GUtil 2.1.9 is in the Mozilla sandbox so the update will be comming soon.
Some version notes:
* Added the posibility to swap mouse button actions (open in new tab – open in current tab, left click – right click). Middle click still opens in background tab.
* Added a chevron functionality to temporarly show all items, until an item is used.
* Added check all/uncheck all functionality to the options dialog. Use with care, you can loose your settings this way.

Happy Firefox browsing.