There is a bug in Firefox 21 with the Windows 7 Taskbar "Jump List" not being updated. (Long thread here: Why do visited sites not show in my jump list? (Win 7 Ultimate).)

Judging from the bug system, the fix will definitely appear in Firefox 24, and there is an effort to move it up to Firefox 22 (beta) and Firefox 23 (aurora).

Thanks for this. I can't remember the last time I had an issue with a part of Firefox that I used very often. Firefox has been relatively trouble-free for me since before it was called Firefox, but after trying every potential fix I found to resolve this issue (in addition to all the clean uninstalls, reinstalls, and reconfigurations) and then seeing nothing come of it each time, it made me seriously debate testing out Chrome as my primary browser. It isn't perfect, but the jump lists are an integral part of my workflow.

As a "quick fix" you could do what the poster did in the other thread: Install Firefox 20.0.1 to rebuild the jump list, then when you're done, reinstall Firefox 21. Obviously you wouldn't want to do this every single time you want to add a new shortcut, but to get the Tasks and Frequent pages back, it might be worth doing once.

Not a bad idea to make a backup of your settings (profile) folder first. This article has tips on that: Back up and restore information in Firefox profiles.

Old versions are available through the downgrade link in this article: Install an older version of Firefox.

Firefox 22 beta 4 reportedly has the fix. I haven't tried it myself.

If you want to try it urgently, you can install the beta version from here: http://www.mozilla.org/firefox/beta/

Otherwise, it will be officially released in a few weeks.

In 23 beta 2 that work slowly.

Hi fchioa, could you explain the problem in more detail? Firefox is slow to update the jump list, or Firefox is slow to launch when you choose certain items on the jump list?