Seems to work normally on Windows XP. Hopefully some other Mac users can test.

OK, I narrowed the problem down to the Torbutton add-on. One needs to update that to the latest version. Then, at least for me, everything worked fine.

I have the same problem in FF12 under OS X 10.6.8. I'm already using the latest version of Torbutton (1.4.5.1), so that's not the cause of my problem. However, when I run Firefox in Safe Mode (with Add-ons disabled), I can indeed drag-and-drop bookmarks again, so evidently there is an Add-on correlation. If I take the time to figure out which one(s) are involved, I'll repost here.

Please see my thread here: https://support.mozilla.org/en-US/questions/926969

For the record, I am using Windows Vista, not a Mac. My problem manifested as danll described, plus more.

I also had the latest Torbutton already installed, but it seemed so unrelated to this problem that I didn't consider it as a cause.

After trying other things and toggling off many extensions it turned out that disabling Torbutton eliminated the problem. You may want to try that. It's not simply a matter of version in use.

It's possible that Torbutton in combination with another extension is the problem, not Torbutton alone. I initially was going to focus on Tab Mix Plus as the sole problem, and it's likely that there may be a compounding effect with TMP. However, since I never used Torbutton anyway, in favor of the Tor desktop bundle, it's just easier to disable and uninstall it rather than devoting more time.

it's the torbutton extension on its own that causes the issue with firefox versions 12 upwards - i also tried it with a fresh test profile. the torbutton extension is no longer maintained by its developers - they recommend a switch to the tor browser bundle, see https://www.torproject.org/torbutton/.

Well, I should have been a little clearer. What worked for me last week was to "upgrade" to Torbutton 1.4.0. Yes, I was using 1.4.5 before, and then I downloaded what was then a featured Tor package (I forget exactly what it was called at the Tor download site). That package (not the bundle), included Torbutton 1.4.0. Huh? I said. How could 1.4.0 be an "upgrade" to 1.4.5? But I just installed it, replacing 1.4.5. It worked.

Curiously, that package download option is now gone. So indeed, it looks like they're pulling their support for Torbutton.

With 1.4.0 it seems to pass muster when I go to the https://check.torproject.org/ site.

There is some weirdness here. This week is pretty different from last week.

Bottom line. I'm using 1.4.0, it seems to be secure, and I can move my bookmarks around. If someone wants to tell me exactly why I shouldn't be using 1.4.0, and why they were offering it last week, I'm listening.

The Torbutton xpi repository is here

https://archive.torproject.org/tor-package-archive/torbutton/

I may experiment with downgrading to see if it works with FF12. Presumably 1.4.5 will work with FF 11 but not 12, while 1.4.0 (and maybe 1.4.3 and 1.4.4) is of course compatible with all versions to date.

Again, I'm not so attached to the button versus their desktop bundle, but it's handy to have in-browser.

If you go to their blog they make a pretty good technical case for the security limitations now inherent in using the button. I'd think they'd intensify as Firefox moves forward into new builds. However, the busg they are accumulating that they don't have the manpower to fix probably don't affect and are't seen by the average casual user.

Yes, I'm aware of the technical limitations of Torbutton, at least very broadly. But I find it a lot easier to use my own Firefox, at least because I have all my bookmarks set up there. (Hence my frustration at not being able to edit my bookmarks!) Thanks for the pointer to the Torbutton download repository. At least that makes it easy to play around with different versions.

I have read that there are about 5 or 6 other add-ons that also inhibit Drag and Drop functionality, not just the Torbutton add-on. The list is somewhere in the main Firefox support section (but it's tough to find the answer there twice).

The generic add-on troubleshooting page is at:

https://support.mozilla.org/en-US/kb/Troubleshooting-extensions-themes#w_disable-all-extensions

That may be the case that there are a number of add-ons that can inhibit drag & drop but, in my case, the problem was definitely TorButton 1.4.5. I disabled each of my add-ons individually, and the problem disappeared when TorButton 1.4.5 was disabled. But I'm using TorButton 1.4.0 now, and everything works.

Perspectoff, you may be thinking of this page, which is somewhat outdated but still useful:

http://kb.mozillazine.org/Problematic_extensions

or this, which is more up-to-date but not annotated:

https://addons.mozilla.org/en-US/firefox/blocked/

Like danll, I can state unequivocally that Torbutton was my problem. I turned off all my extensions,turned them back on in groups of ten, then restarted FF to test and had no problems until Torbutton was enabled (which was in the last or next-to-last group enabled). I have approximately 100 extensions installed, with about 15 disabled, including the most popular ones for their functions (AdBlock, FlashBlock, Greasemonkey, FoxyProxy, etc.).

It's very likely that I'd have at least one of the other problematic extensions installed. If the add-on is too obscure or has relatively fewer users we'd be less likely to hear about it's problems in the first place.

However, some other extension exhibiting the same problem could be because its in combination with yet another extension (which might be very difficult to find), or because of some change in Firefox with a new build. Torbutton was fine until I installed FF v11.0. Once I uninstalled Tb v1.4.5 and installed the previous version, 1.4.4.1, everything works normally again.

Thanks lm108, that's useful to know that 1.4.4.1 works. Presumably that's a more mature version than 1.4.0. I'll install that and start using it.

Excuse me. I meant to say that the problem disappeared when TorButton 1.4.5 was *removed*. Again, just turning it off doesn't help.