I'm wondering how to move the focused tab around, to right or left, using a keyboard shortcut in 12.04?
After a Google search I found the shortcut Ctrl + (L/R)Arrows, but it seems to work only in Windows, not in Ubuntu.
Firefox 19 added shortcuts to move tabs:
However, there is still no built-in shortcut to move the current tab to the start or end. If you need those shortcuts, keep the extension and in its preferences set the left/right shortcuts to something you don't use.
That can be done with an add-on, that allows you to define your own shortcuts to move the tabs into Firefox. Click on the link, to install this Add-On. Once installed, restart Firefox, go into add-on, and click on Preferences, to set the shortcuts. Close the window, and you're set.
Notice that the Move tab is the last one, and in the second image it moved to the first tab.
This extension for Firefox claims to move the focused tab forwards and backwards, respectively, with Ctrl+Shift+Page Up and Ctrl+Shift+Page Down.
Moving the focused tab to the start or end, respectively, can be done with Ctrl+Shift+Home and Ctrl+Shift+End
Mozilla Support says that Ctrl+Up Arrow or Ctrl+Left Arrow moves the focused tab left and similarly for right. This, however, did not work for me (Firefox 14.0.1, Ubuntu 12.04LTS).