Need a few more options for your Firefox tabs?  Twanno’s Tab Clicking Options extension for Firefox should do the trick.  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.
The events you can assign an action to are:

Double clicking
Clicking with middle mouse button
Left clicking with control-key (or meta-key on Mac) pressed
Left clicking with alt-key pressed
Left clicking with shift-key pressed
And the actions [...]

Now this extension does add a lot of functionality when it comes to searching. The SearchWords extension for Firefox allows you to assign keywords to your search engines inside of the browser.
Assign keywords to your search engines for quick and easy access to all of your search engines without using the search bar and without having to switch from your current search engine. To use, add keywords to your search engines via the search engine manager and [...]