Twanno's Firefox Extensions

Duplicate Tab

Version: 1.0.2
  Firefox 2.0 - 3.1a1pre
  Seamonkey 1.1 - 2.0a1

Duplicate Tab allows you to clone a tab along with its history. So you can browse forward or backward in the history of the cloned tab, while reading the current page in the original tab. You can duplicate a tab to a new window or to the same window as the original tab.
Duplicate Tab also allows you to open a link in a new duplicated tab, so the new tab will contain the history of the original tab.
Another feature is the ability to merge windows: When you have several windows open, you can merge all tabs in all windows into one window, thereby closing the other windows.

More information
MozillaZine Forum thread

Tab Clicking Options

Version: 0.6.9
  Firefox 1.0 - 3.0
  Mozilla Suite 1.6 - 1.7
  Seamonkey 1.0 - 2.0a1

With the Tab Clicking Options extension it is possible to set various actions to different clicking events on the tab bar or a tab in the firefox browser. To the following mouse click events can be assigned an action to:

And the following actions can be assigned to any of the previous events performed on a tab or the tab bar:

Tab Clicking Options also recognizes other extensions like SessionSaver, IE View, UndoCloseTab, Click2Tab and Duplicate Tab, so actions from those extensions can be assigned to clicking events as well.

More information
MozillaZine Forum thread

Close Tab On Double Click

Get Tab Clicking Options

Tab Clicking Options supersedes Close Tab On Double Click (CTODC). Therefore CTODC is not longer being updated. If you want to have a tab closed on double click with Tab Clicking Options, set double clicking on a tab to "Close Tab" in the options dialog available from Tools->Extensions (double click the Tab Clicking Options entry to open the options dialog).
For users who don't want to use Tab Clicking Options and don't care about the possibility of a not working extension by firefox 1.1, I have a version of Close Tab On Double Click, which worked with Firefox versions upto Firefox PR, made compatible for Firefox 0.8 to 3.0. As long as the tab-clicking code in Firefox does not change, this extension should work fine (except from possible interference with other extensions). This extension works on the Mozilla Suite (tested on 1.7.3 / 1.8a5 nightly) and SeaMonkey too Get it here