Double Click On Page Closes Tab от Geoffrey De Belie

Double click on a page to close the current tab. You can double click with your left mouse button by pressing the left mouse button twice in quick succession.

Note: use the about:config setting browser.tabs.closeTabByDblclick to close tabs by double clicking on them.

This addon does not work on these pages:
* about: pages
* priviledged websites such as addons.mozilla.org (caused by security restrictions)
* Flash websites