Did you check the browser.taskbar.lists prefs on the about:config page?

• http://kb.mozillazine.org/about:config

Checked about:config and nothing is changed from default values. Here are my entries:

browser.taskbar.lists.enabled = true browser.taskbar.lists.frequent.enabled = true browser.taskbar.lists.maxListItemCount = 7 browser.taskbar.lists.recent.enabled = false browser.taskbar.lists.refreshInSeconds = 120 browser.taskbar.lists.tasks.enabled = true

Apparently this bug got pushed to the release channel now. After updating to 15.0.1, restarting Firefox used a new icon on the taskbar rather than the one that had been pinned before (as usual). But when I right click on the new icon to pin it, nothing happens. There's no jumplist at all, not even the minimal one that pops up for programs that don't make use of jumplist functionality. So I can't even pin the icon to my taskbar.

Same here, with Firefox 15.0.1 and Windows 7 Professional 64-bit (6.1, Build 7601) Service Pack 1 (7601.win7sp1_gdr.120503-2030) running on a Dell XPS-9100 (Intel 4-core) with 12 GB RAM.

UPDATE: This bug was fixed with Firefox 16.0 beta. Once it was installed, I was able to pin again. Multiple updates since then and still able to pin.

And now it's broken again with 17.0.1. Mozilla seems to have a really annoying habit of fixing it with one update, then breaking it again with the next one. They've been doing this since 13, or maybe even 11. It's getting ridiculous now.

EDIT: Fixed with 18.0, broken again with 18.0.1. I give up.