There is a mod in the comments below that works fine in Firefox 3.6+ and its clean, if that doesnt work for you (or you dont trust) you can download Tabberwocky; EXCELENT addon, saved me; no longer have 5 addons, just 1. Replaced T.O.R., hide close, button, tab reziser, bookmarks and history in new tab, show progress bar in each tab, open many links by highlight them (i dont remember some addons name, just posting what they did).
Only ONE addon to reeplace FIVE.
I loved T.O.R. and I thank the developers hard work. Thank You.