It actually work for me Firefox 3.6 Beta 4
1, Type about:config
in the awesome bar (address bar). Ignore the caution message and proceed.
2, Type browser.taskbar.previews.enable
in the filter bar.
3, Now, you will be displayed a single entry whose current value is False
. Double click on the entry to
change its value to True
Also can check this thread for more customization : http://www.sevenforums.com/customiza...ompletely.html